Solid-state imaging device and electronic apparatus

ABSTRACT

The present technology relates to a solid-state imaging device and an electronic apparatus capable of improving the accuracy of phase difference detection while suppressing degradation of a picked-up image. There is provided a solid-state imaging device including: a pixel array unit, a plurality of pixels being two-dimensionally arranged in the pixel array unit, a plurality of photoelectric conversion devices being formed with respect to one on-chip lens in each of the plurality of pixels, a part of at least one of an inter-pixel separation unit formed between the plurality of pixels and an inter-pixel light blocking unit formed between the plurality of pixels protruding toward a center of the corresponding pixel in a projecting shape to form a projection portion. The present technology is applicable to, for example, a CMOS image sensor including a pixel for detecting the phase difference.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of and claims priority to U.S.patent application Ser. No. 18/129,383, filed Mar. 31, 2023, which is acontinuation of and claims priority to U.S. patent application Ser. No.17/354,191, filed on Jun. 22, 2021, now U.S. Pat. No. 11,688,747, whichis a continuation of and claims priority to U.S. patent application Ser.No. 16/486,936, filed on Aug. 19, 2019, now U.S. Pat. No. 11,075,236,which is a national stage application under 35 U.S.C. 371 and claims thebenefit of PCT Application No. PCT/JP2018/020309, having aninternational filing date of May 28, 2018, which designated the UnitedStates, which PCT application claimed the benefit of Japanese PatentApplication Nos. 2017-105715, filed May 29, 2017, and 2018-095949, filedMay 18, 2018, the entire disclosures of each of which are incorporatedherein by reference.

TECHNICAL FIELD

The present technology relates to a solid-state imaging device and anelectronic apparatus, and particularly to a solid-state imaging deviceand an electronic apparatus capable of improving the accuracy of phasedifference detection while suppressing degradation of a picked-up image.

BACKGROUND ART

In recent years, a solid-state imaging device in which image surfacephase difference detection pixels are arranged is used for increasingthe speed of autofocus.

In this kind of solid-state imaging device, a method of partiallyblocking light by a metal film or the like is often and generally usedfor pupil-dividing light condensed by an on-chip lens. However, since itis difficult to use information acquired from a light-blocking pixel asinformation regarding a picked-up image, there is a need to useinformation acquired from a surrounding pixel for interpolation.

Further, such a solid-state imaging device has a disadvantage that sinceit is difficult to arrange the light-blocking pixels on the entiresurface with respect to effective pixels, the amount of light receivedby the entire phase difference pixels is reduced, which reduces theaccuracy of phase difference detection particularly when the amount oflight is small.

As a technology for avoiding this, there is a method of performingpupil-division by embedding a plurality of photoelectric conversiondevices under one on-chip lens. Such a method is used in, for example, asolid-state imaging device for a single-lens reflex camera or a cameraincorporated in a smartphone (e.g., see Patent Literature 1).

CITATION LIST Patent Literature

-   Patent Literature 1: Japanese Patent Application Laid-open No.    2002-165126

DISCLOSURE OF INVENTION Technical Problem

Meanwhile, in a solid-state imaging device including two photoelectricconversion devices located immediately below a single on-chip lens, anoutput of one photoelectric conversion device is mixed with an output ofthe other photoelectric conversion device, which reduces the accuracy ofphase difference detection in some cases.

As a technology for avoiding this, providing a physical separation unitbetween two photoelectric conversion devices is conceivable. However,particularly in the case where it is in focus, this separation unitinterferes with photoelectric conversion in the photoelectric conversiondevice, which reduces the sensitivity. In addition, light scatteringoccurs in this separation unit, which deteriorates the spectralcharacteristics. As a result, the image quality of a picked-up image maybe reduced.

The present technology has been made in view of the above circumstancesto make it possible to improve the accuracy of phase differencedetection while suppressing degradation of a picked-up image.

Solution to Problem

A solid-state imaging device according to an aspect of the presenttechnology is a solid-state imaging device, including: a pixel arrayunit, a plurality of pixels being two-dimensionally arranged in thepixel array unit, a plurality of photoelectric conversion devices beingformed with respect to one on-chip lens in each of the plurality ofpixels, a part of at least one of an inter-pixel separation unit formedbetween the plurality of pixels and an inter-pixel light blocking unitformed between the plurality of pixels protruding toward a center of thecorresponding pixel in a projecting shape to form a projection portion.

In a solid-state imaging device according to an aspect of the presenttechnology, a pixel array unit is provided, a plurality of pixels beingtwo-dimensionally arranged in the pixel array unit, a plurality ofphotoelectric conversion devices being formed with respect to oneon-chip lens in each of the plurality of pixels, a part of at least oneof an inter-pixel separation unit formed between the plurality of pixelsand an inter-pixel light blocking unit formed between the plurality ofpixels protruding toward a center of the corresponding pixel in aprojecting shape to form a projection portion.

A solid-state imaging device according to an aspect of the presenttechnology is a solid-state imaging device, including: a pixel arrayunit, a plurality of pixels being two-dimensionally arranged in thepixel array unit, one photoelectric conversion device being formed ineach of the plurality of pixels, the pixel array unit including pixelsarranged with respect to one on-chip lens, a part of at least one of aninter-pixel separation unit formed between pixels constituting thepixels arranged with respect to the one on-chip lens and an inter-pixellight blocking unit formed between the pixels constituting the pixelsarranged with respect to the one on-chip lens protruding toward a centerof the pixels arranged with respect to the one on-chip lens in aprojecting shape to form a projection portion.

In solid-state imaging device according to an aspect of the presenttechnology, a pixel array unit is provided, a plurality of pixels beingtwo-dimensionally arranged in the pixel array unit, one photoelectricconversion device being formed in each of the plurality of pixels, thepixel array unit including pixels arranged with respect to one on-chiplens, a part of at least one of an inter-pixel separation unit formedbetween pixels constituting the pixels arranged with respect to the oneon-chip lens and an inter-pixel light blocking unit formed between thepixels constituting the pixels arranged with respect to the one on-chiplens protruding toward a center of the pixels arranged with respect tothe one on-chip lens in a projecting shape to form a projection portion.

An electronic apparatus according to an aspect of the present technologyis an electronic apparatus, including: a solid-state imaging deviceincluding a pixel array unit, a plurality of pixels beingtwo-dimensionally arranged in the pixel array unit, a plurality ofphotoelectric conversion devices being formed with respect to oneon-chip lens in each of the plurality of pixels, a part of at least oneof an inter-pixel separation unit formed between the plurality of pixelsand an inter-pixel light blocking unit formed between the plurality ofpixels protruding toward a center of the corresponding pixel in aprojecting shape to form a projection portion.

In a solid-state imaging device mounted on an electronic apparatusaccording to an aspect of the present technology, a pixel array unit isprovided, a plurality of pixels being two-dimensionally arranged in thepixel array unit, a plurality of photoelectric conversion devices beingformed with respect to one on-chip lens in each of the plurality ofpixels, a part of at least one of an inter-pixel separation unit formedbetween the plurality of pixels and an inter-pixel light blocking unitformed between the plurality of pixels protruding toward a center of thecorresponding pixel in a projecting shape to form a projection portion.

Advantageous Effects of Invention

According to an aspect of the present technology, it is possible toimprove the accuracy of phase difference detection while suppressingdegradation of a picked-up image.

It should be noted that the effect described here is not necessarilylimitative and may be any effect described in the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing a configuration example of a solid-stateimaging device to which an embodiment of the present technology isapplied.

FIG. 2 is a cross-sectional view showing a structure of a pixelincluding two photoelectric conversion devices located immediately belowone on-chip lens.

FIG. 3 is a diagram showing an output result depending on an incidenceangle of light for each photoelectric conversion device.

FIG. 4 is a diagram showing a structure of a pixel including twophotoelectric conversion devices located immediately below one on-chiplens.

FIG. 5 is a diagram showing a structure of a pixel for improving theaccuracy of phase difference detection.

FIG. 6 is a diagram showing a plane layout of a general pixel.

FIG. 7 is a cross-sectional view showing a structure of a general pixel.

FIG. 8 is a diagram describing an N-type potential in a silicon layer ofa general pixel.

FIG. 9 is a diagram showing a plane layout of a pixel in a firstembodiment.

FIG. 10 is a diagram describing an N-type potential in a silicon layerof the pixel in the first embodiment.

FIG. 11 is a first cross-sectional view showing a structure of the pixelin the first embodiment.

FIG. 12 is a second cross-sectional view showing the structure of thepixel in the first embodiment.

FIG. 13 is a third cross-sectional view showing the structure of thepixel in the first embodiment.

FIG. 14 is a three-dimensional diagram showing the structure of thepixel in the first embodiment.

FIG. 15 is a three-dimensional diagram showing a structure of a pixel ina second embodiment.

FIG. 16 is a three-dimensional diagram showing a structure of a pixel ina third embodiment.

FIG. 17 is a plan view showing a structure of a pixel in a fourthembodiment.

FIG. 18 is a plan view showing a first modified example of the structureof the pixel in the fourth embodiment.

FIG. 19 is a plan view showing a second modified example of thestructure of the pixel in the fourth embodiment.

FIG. 20 is a plan view showing a third modified example of the structureof the pixel in the fourth embodiment.

FIG. 21 is a plan view showing a fourth modified example of thestructure of the pixel in the fourth embodiment.

FIG. 22 is a plan view showing a structure of a pixel in a fifthembodiment.

FIG. 23 is a diagram describing a relationship between a diameter of aspot of incident light and a length of a projection portion.

FIG. 24 is a plan view showing a structure of a pixel in a sixthembodiment.

FIG. 25 is a plan view showing a structure of a pixel in a seventhembodiment.

FIG. 26 is a plan view showing a modified example of the structure ofthe pixel in the seventh embodiment.

FIG. 27 is a plan view showing a structure of a pixel in an eighthembodiment.

FIG. 28 is a diagram showing a plane layout of a pixel in a ninthembodiment.

FIG. 29 is a diagram describing an N-type potential in a silicon layerof the pixel in the ninth embodiment.

FIG. 30 is a cross-sectional view showing a structure of the pixel inthe ninth embodiment.

FIG. 31 is a cross-sectional view showing a first example of a structureof a pixel in a tenth embodiment.

FIG. 32 is a cross-sectional view showing a second example of thestructure of the pixel in the tenth embodiment.

FIG. 33 is a cross-sectional view showing a third example of thestructure of the pixel in the tenth embodiment.

FIG. 34 is a cross-sectional view showing a fourth example of thestructure of the pixel in the tenth embodiment.

FIG. 35 is a cross-sectional view showing a fifth example of thestructure of the pixel in the tenth embodiment.

FIG. 36 is a cross-sectional view showing a sixth example of thestructure of the pixel in the tenth embodiment.

FIG. 37 is a cross-sectional view showing a seventh example of thestructure of the pixel in the tenth embodiment.

FIG. 38 is a cross-sectional view showing an eighth example of thestructure of the pixel in the tenth embodiment.

FIG. 39 is a cross-sectional view showing a ninth example of thestructure of the pixel in the tenth embodiment.

FIG. 40 is a cross-sectional view showing a tenth example of thestructure of the pixel in the tenth embodiment.

FIG. 41 is a cross-sectional view showing an eleventh example of thestructure of the pixel in the tenth embodiment.

FIG. 42 is a diagram schematically illustrating a potential distributionof the pixel in the tenth embodiment.

FIG. 43 is a cross-sectional view showing a first example of a structureof a pixel in an eleventh embodiment.

FIG. 44 is a cross-sectional view showing a second example of thestructure of the pixel in the eleventh embodiment.

FIG. 45 is a cross-sectional view showing a third example of thestructure of the pixel in the eleventh embodiment.

FIG. 46 is a cross-sectional view showing a fourth example of thestructure of the pixel in the eleventh embodiment.

FIG. 47 is a cross-sectional view showing a fifth example of thestructure of the pixel in the eleventh embodiment.

FIG. 48 is a cross-sectional view showing a sixth example of thestructure of the pixel in the eleventh embodiment.

FIG. 49 is a cross-sectional view showing a first example of a structureof a pixel in a twelfth embodiment.

FIG. 50 is a diagram showing an output result corresponding to anincident angle of light for each photoelectric conversion device.

FIG. 51 is a cross-sectional view showing a second example of thestructure of the pixel in the twelfth embodiment.

FIG. 52 is a cross-sectional view showing a third example of thestructure of the pixel in the twelfth embodiment.

FIG. 53 is a cross-sectional view showing a fourth example of thestructure of the pixel in the twelfth embodiment.

FIG. 54 is a cross-sectional view showing a fifth example of thestructure of the pixel in the twelfth embodiment.

FIG. 55 is a cross-sectional view showing a sixth example of thestructure of the pixel in the twelfth embodiment.

FIG. 56 is a cross-sectional view showing a seventh example of thestructure of the pixel in the twelfth embodiment.

FIG. 57 is a diagram showing an example of the planar layout and crosssection of a pixel in a thirteenth embodiment.

FIG. 58 is a cross-sectional view showing a structure of a generalpixel.

FIG. 59 is a cross-sectional view showing a first example of a structureof the pixel in the thirteenth embodiment.

FIG. 60 is a cross-sectional view showing a second example of thestructure of the pixel in the thirteenth embodiment.

FIG. 61 is a cross-sectional view showing a third example of thestructure of the pixel in the thirteenth embodiment.

FIG. 62 is a diagram showing a circuit configuration of a pixel in eachembodiment.

FIG. 63 is a block diagram showing a configuration example of anelectronic apparatus including a solid-state imaging device to which anembodiment of the present technology is applied.

FIG. 64 is a diagram showing a usage example of a solid-state imagingdevice to which an embodiment of the present technology is applied.

FIG. 65 is a diagram showing an overview of a configuration example of astacked-type solid-state imaging device to which the technologyaccording to the present disclosure can be applied.

FIG. 66 is a cross-sectional view showing a first configuration exampleof the stacked-type solid-state imaging device.

FIG. 67 is a cross-sectional view showing a second configuration exampleof the stacked-type solid-state imaging device.

FIG. 68 is a cross-sectional view showing a third configuration exampleof the stacked-type solid-state imaging device.

FIG. 69 is a cross-sectional view showing another configuration exampleof a stacked-type solid-state imaging device to which the technologyaccording to the present disclosure can be applied.

FIG. 70 is a block diagram showing an example of a schematicconfiguration of a vehicle control system.

FIG. 71 is an explanatory diagram showing examples of mounting positionsof a vehicle exterior information detection unit and image captureunits.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present technology will be describedwith reference to the drawings. Note that descriptions will be made inthe following order.

-   -   1. Configuration of Solid-state Imaging Device    -   2. Prerequisite Technology    -   3. Embodiments of Present Technology    -   (1) First Embodiment: Structure in which Projection Portion Is        Provided in Inter-pixel Si Separation (Basic Structure)    -   (2) Second Embodiment: Structure in which Projection Portion Is        Provided in Inter-pixel Light Blocking    -   (3) Third Embodiment: Structure in which Projection Portion Is        Provided in Inter-pixel Si Separation and Inter-pixel Light        Blocking    -   (4) Fourth Embodiment: Structure in which Projection Portion Is        Formed For R, G, or B Pixel    -   (5) Fifth Embodiment: Structure in which Length of Projection        Portion Is Adjusted    -   (6) Sixth Embodiment: Structure in which Length of Projection        Portion Is Adjusted for Each Pixel    -   (7) Seventh Embodiment: Structure in which Elliptical On-chip        Lens Is Used    -   (8) Eighth Embodiment: Structure in which Plurality of Pixels        Are Arranged with respect to Single On-chip Lens    -   (9) Ninth Embodiment: Structure in which Physical Separation Is        Performed from Surface Opposite to Light Incident Side    -   (10) Tenth Embodiment: Structure in which Fixed Charge Amount Is        Changed between Central Portion of PD and Other Portions    -   (11) Eleventh Embodiment: Structure in which Central Portion of        PDs of Same Colors Is Low Refractive Area and Central Portion of        PDs of Different Colors Is Metal Area    -   (12) Twelfth Embodiment: Structure in Which OCL Is Formed of        Plurality of Types of Substances Having Different Refractive        Indexes    -   (13) Thirteenth Embodiment: Structure in which Vertical        Transistor Is Formed In Central Portion of PDs of Same Colors    -   4. Circuit Configuration of Pixel    -   5. Modified Example    -   6. Configuration of Electronic Apparatus    -   7. Usage Example of Solid-state Imaging Device    -   8. Configuration Example of Stacked-type Solid-state Imaging        Device to which Technology according to Present Disclosure Can        Be Applied    -   9. Application Example to Moving Body

1. Configuration of Solid-state Imaging Device

(Configuration Example of Solid-State Imaging Device)

FIG. 1 is a diagram showing a configuration example of a solid-stateimaging device to which an embodiment of the present technology isapplied.

A CMOS image sensor 10 shown in FIG. 1 is an example of a solid-stateimaging device using a CMOS (Complementary Metal Oxide Semiconductor).The CMOS image sensor 10 captures incident light (image light) from anobject via an optical lens system (not shown), converts the light amountof the incident light imaged on an imaging surface into an electricsignal on a pixel-by-pixel basis, and outputs the electric signal as apixel signal.

In FIG. 1 , the CMOS image sensor 10 includes a pixel array unit 11, avertical drive circuit 12, a column signal processing circuit 13, ahorizontal drive circuit 14, an output circuit 15, a control circuit 16,and an input/output terminal 17.

Note that in the following description, as the pixels to be arranged inthe pixel array unit 11, a pixel 200, a pixel 300, a pixel 400, and apixel 500 in addition to a pixel 100 will be described.

In the pixel array unit 11, a plurality of pixels 100 are arrangedtwo-dimensionally (in a matrix pattern). The plurality of pixels 100each include a photodiode (PD) as a photoelectric conversion device, anda plurality of pixel transistors. For example, the plurality of pixeltransistors include a transfer transistor, a reset transistor, anamplification transistor, and a selection transistor.

The vertical drive circuit 12 includes, for example, a shift register,selects a predetermined pixel drive line 21, supplies a pulse fordriving the pixels 100 to the selected pixel drive line 21, and drivesthe pixels 100 row by row. Specifically, the vertical drive circuit 12sequentially selects and scans each pixel 100 in the pixel array unit 11in the vertical direction row by row, and supplies a pixel signal basedon the signal charge (charge) generated depending on the amount ofreceived light in the photoelectric conversion device of each pixel 100to the column signal processing circuit 13 through a vertical signalline 22.

The column signal processing circuit 13 is arranged for each column ofthe pixels 100, and performs, for each pixel column, signal processingsuch as noise removal on signals output from the pixels 100 in one row.For example, the column signal processing circuit 13 performs signalprocessing such as correlated double sampling (CDS) for removing fixedpattern noise unique to the pixel and AD (Analog Digital) conversion.

The horizontal drive circuit 14 includes, for example, a shift register,sequentially selects each of the column signal processing circuits 13 bysequentially outputting a horizontal scanning pulse, and causes each ofthe column signal processing circuits 13 to output a pixel signal to ahorizontal signal line 23.

The output circuit 15 performs signal processing on the signalsequentially supplied from each of the column signal processing circuits13 through the horizontal signal line 23, and outputs the processedsignal. Note that the output circuit 15 performs, for example, onlybuffering, or black level adjustment, column variation correction,various types of digital signal processing, and the like in some cases.

The control circuit 16 controls the operation of the respective units ofthe CMOS image sensor 10.

Further, the control circuit 16 generates a clock signal and a controlsignal, which are used as the reference of the operation of the verticaldrive circuit 12, the column signal processing circuit 13, thehorizontal drive circuit 14, and the like, on the basis of a verticalsynchronous signal, a horizontal synchronous signal, and a master clocksignal. The control circuit 16 outputs the generated clock signal andcontrol signal to the vertical drive circuit 12, the column signalprocessing circuit 13, the horizontal drive circuit 14, and the like.

The input/output terminal 17 transmits/receives signals to/from theoutside.

The CMOS image sensor 10 in FIG. 1 configured as described above is aCMOS image sensor called a column AD method in which the column signalprocessing circuits 13 that perform CDS processing and AD conversionprocessing are arranged for each pixel column. Further, the CMOS imagesensor in FIG. 1 may be, for example, a backside irradiation type CMOSimage sensor.

2. Prerequisite Technology

(Structure of Pixel)

FIG. 2 is a cross-sectional view showing a structure of a pixel 700including two photoelectric conversion devices 713A and 713B locatedimmediately below one on-chip lens 711. Note that the pixel 700 includesa color filter 712, an inter-pixel light blocking unit 714, aninter-pixel separation unit 715, and transfer gates 151A and 151B inaddition to the on-chip lens 711 and the photoelectric conversiondevices 713A and 713B.

In FIG. 2 , the pixel 700 has a structure in which two photoelectricconversion devices of the photoelectric conversion device 713A and thephotoelectric conversion device 713B are provided with respect to theone on-chip lens 711. Note that in the following description, such astructure will be referred to also as the 2PD structure.

In the pixel 700, an incident light IL condensed by the on-chip lens 711is transmitted through the color filter 712, and applied to aphotoelectric conversion area of the photoelectric conversion device713A or the photoelectric conversion device 713B.

In the example of FIG. 2 , the incident light IL is intensively appliedto the photoelectric conversion area of the photoelectric conversiondevice 713A in accordance with an incidence angle θi of the incidentlight IL. At this time, ideally, when the output of the photoelectricconversion device 713A is represented by 100, the output of thephotoelectric conversion device 713B should be 0. However, actually, acertain amount of output is performed from the photoelectric conversiondevice 713B.

FIG. 3 shows an output result depending on the incidence angle θi oflight for each photoelectric conversion device 713. In FIG. 3 , theoutput of the photoelectric conversion device 713A is represented by asolid line curve A, and the output of the photoelectric conversiondevice 713B is represented by a dotted line curve B.

In FIG. 3 , the output values in the curve A depending on the output ofthe photoelectric conversion device 713A and the curve B depending onthe output of the photoelectric conversion device 713B match in the casewhere the incidence angle θi is 0 degrees, i.e., light is incident fromdirectly above. That is, the curve A and the curve B have a symmetricalrelationship with the output when the incidence angle θi=0 as thesymmetrical axis.

With such a relationship, for example, in the case where the incidentlight IL is intensively applied to the photoelectric conversion area ofthe photoelectric conversion device 713A shown in FIG. 2 , an increasein not only the output of the photoelectric conversion device 713A butalso the output of the photoelectric conversion device 713B results inreduction of the accuracy of phase difference detection. For example,focusing on an incidence angle θa in FIG. 3 , not only the output of thephotoelectric conversion device 713A but also the output of thephotoelectric conversion device 713B is performed.

That is, although the photoelectric conversion device 713A and thephotoelectric conversion device 713B are used in pairs for phasedifference detection, mixing of the output of one photoelectricconversion device 713 (713A or 713B) with the output of the otherphotoelectric conversion device 713 (713B or 713A) results in reductionof the detection accuracy.

Now, as a structure for preventing the output of one photoelectricconversion device 713 from mixing with the output of the otherphotoelectric conversion device 713, a structure in which a physicalseparation unit is formed between the photoelectric conversion device713A and the photoelectric conversion device 713B formed in a silicon(Si) layer will be considered.

Specifically, the pixel 700 having the 2PD structure corresponding toFIG. 2 is shown in FIG. 4 , and the inter-pixel light blocking unit 714and the inter-pixel separation unit 715 are formed but no physicalseparation unit is formed between the photoelectric conversion device713A and the photoelectric conversion device 713B as shown in the planview or X-X′ cross-sectional view.

Meanwhile, in FIG. 5 , a pixel 800 in which a physical separation unitis provided between photoelectric conversion devices is shown. In thepixel 800 shown in FIG. 5 , an inter-device separation unit 816 isformed in a silicon layer between a photoelectric conversion device 813Aand a photoelectric conversion device 813B, and the photoelectricconversion device 813A and the photoelectric conversion device 813B arephysically separated from each other.

Since the inter-device separation unit 816 is formed in the pixel 800having the 2PD structure as described above, it is possible to improvethe accuracy of phase difference detection by preventing the output ofone photoelectric conversion device 813 (813A or 813B) from mixing withthe output of the other photoelectric conversion device 813 (813B or813A).

However, in the case where the inter-device separation unit 816 isformed in the pixel 800 shown in FIG. 5 , particularly when it is infocus, the inter-device separation unit 816 may interfere withphotoelectric conversion in a photoelectric conversion area of thephotoelectric conversion device 813A or the photoelectric conversiondevice 813B, which reduces the sensitivity. In addition, it is shownthat light scattering (“SL” in FIG. 5 ) occurs in the inter-deviceseparation unit 816, which deteriorates the spectral characteristics,and thus, the image quality of a picked-up image is reduced.

3. Embodiments of Present Technology

Next, a structure of the pixel 100 to which an embodiment of the presenttechnology will be described. Note that after describing a structure ofa general pixel 900 with reference to FIG. 6 to FIG. 8 for comparison,the structure of the pixel 100 to which an embodiment of the presenttechnology will be described with reference to FIG. 9 to FIG. 62 .

(Structure of General Pixel)

First, a structure of the general pixel 900 will be described withreference to FIG. 6 to FIG. 8 . FIG. 6 is a diagram showing a planelayout of the general pixel 900. Note that the pixel 900 includes anon-chip lens 911, a color filter 912, photoelectric conversion device913A and 913B, an inter-pixel light blocking unit 914, an inter-pixelseparation unit 915, and transfer gates 951A and 951B.

In FIG. 6 , the pixels 900 in four rows and four columns arranged in apartial area among a plurality of pixels 900 arranged two-dimensionally(in a matrix pattern) in a pixel array unit are shown as a typicalexample. Further, in FIG. 6 , i-rows and j-columns of the pixels 900arranged in the pixel array unit are represented by pixel 900-ij.

In this pixel array unit, the plurality of pixels 900 aretwo-dimensionally arranged in a Bayer pattern. Note that the Bayerpattern represents an arrangement pattern in which green (G) pixels arearranged in a checkered pattern, and red (R) pixels and blue (B) pixelsare alternately arranged for each line in the remaining area.

Note that in the following description, a pixel in which an R colorfilter that causes red (R) wavelength components to be transmittedtherethrough is provided as a color filter and charges corresponding tolight of R components are obtained from light transmitted through the Rcolor filter will be referred to as R pixel. Further, a pixel in whichcharges corresponding to light of G components are obtained from lighttransmitted through a G color filter that causes green (G) wavelengthcomponents to be transmitted therethrough will be referred to as Gpixel. Further, a pixel in which charges corresponding to light of Bcomponents are obtained from light transmitted through a B color filterthat causes blue (B) wavelength components to be transmittedtherethrough will be referred to as B pixel.

In the pixel array unit, each of the pixels 900 is a square unit pixelhaving the 2PD structure, and the pixels 900 are physically separated inthe silicon layer by the inter-pixel separation unit 915 arranged in asquare lattice. Note that although not shown in FIG. 6 , in this pixelarray unit, the inter-pixel light blocking unit 914 is arranged in asquare lattice similarly to the inter-pixel separation unit 915.

Further, since each of the pixels 900 has the 2PD structure, aphotoelectric conversion area of the photoelectric conversion device913A and a photoelectric conversion area of the photoelectric conversiondevice 913B are formed in the silicon layer. These photoelectricconversion areas are separated by an impurity in the silicon layer asshown by dotted lines in the column direction in FIG. 6 .

The X-X′ cross section in the plan view shown in FIG. 6 can berepresented by the cross-sectional view shown in FIG. 7 . Note thatassumption is made that the upper left pixel 900 in the pixelarrangement in four rows and four columns shown in FIG. 6 is a pixel900-11 in this example. Therefore, the pixels 900 shown in the X-X′cross section are four pixels of a G pixel 900-41, a B pixel 900-42, a Gpixel 900-43, and a B pixel 900-44.

In FIG. 7 , the G pixel 900-41 has the 2PD structure including thephotoelectric conversion device 913A and the photoelectric conversiondevice 913B. In the photoelectric conversion device 913A, chargescorresponding to light of G components are generated from light that iscondensed by the on-chip lens 911 and transmitted through the G colorfilter 912. Further, in the photoelectric conversion device 913B,charges corresponding to light of G components are generated, similarlyto the photoelectric conversion device 913A.

In the G pixel 900-43, charges corresponding to light of G componentsare generated by the photoelectric conversion device 913A and thephotoelectric conversion device 913B, similarly to the G pixel 900-41.Further, in the B pixel 900-42 and the B pixel 900-44, chargescorresponding to light of B components are generated by thephotoelectric conversion device 913A and the photoelectric conversiondevice 913B.

The charges generated by the photoelectric conversion device 913A andthe photoelectric conversion device 913B in each pixel 900 in this wayare read via the transfer gate 951A and the transfer gate 951B, and usedas information regarding phase difference detection.

FIG. 8 is a plan view of a surface (light incident surface) of the pixel900 on the light incident side, and an N-type potential in the siliconlayer is shown. Specifically, in the pixels 900 physically separated bythe inter-pixel separation unit 915 formed in a square lattice, thephotoelectric conversion area of the photoelectric conversion device913A and the photoelectric conversion area of the photoelectricconversion device 913B are formed as N-type areas, and areas other thanthese photoelectric conversion areas are formed as P-type areas.

In the pixel 900 having such a structure, since charges are not storedin the P-type area other than the photoelectric conversion area, whichof the photoelectric conversion device 913A and the photoelectricconversion device 913B charges generated in the P-type area move to isunknown. Note that in the N-type photoelectric conversion area, whenconsidering the cross section thereof, since the concentration is higheras it is closer to the transfer gate 951, the concentration is low onthe side of the light incident surface. Therefore, in the photoelectricconversion area, charges generated on the side of the light incidentsurface in which the N-type concentration is low are difficult to draw.

Specifically, in FIG. 8 , since the contribution of isolation betweenthe photoelectric conversion devices in P-type areas A1 and A2 is low,it is desired to separate the photoelectric conversion device 913A andthe photoelectric conversion device 913B.

In the case of only providing a physical separation unit (inter-deviceseparation unit 816 in FIG. 5 ) between the photoelectric conversiondevice 913A and the photoelectric conversion device 913B, the imagequality of a picked-up image is reduced as described above.

In this regard, the technology according to the present disclosure(present technology) makes it possible to improve the accuracy of phasedifference detection while suppressing degradation of a picked-up imageby providing a projection portion that protrudes from the inter-pixelseparation unit or the inter-pixel light blocking unit in a projectingshape with respect to the P-type areas A1 and A2 to divide thedestination of charges generated in the P-type area.

Hereinafter, the specific content of the present technology will bedescribed with a first embodiment to a ninth embodiment. First, astructure in which a projection portion is provided will be described inthe first embodiment to the ninth embodiment, and then, other structurewill be described in the tenth embodiment to the thirteenth embodiment.

(1) First Embodiment

(Plane Layout of Pixel)

FIG. 9 is a diagram showing a plane layout of the pixels 100 in a firstembodiment.

In FIG. 9 , pixels 100 in four rows and four columns arranged in apartial area among the plurality of pixels 100 two-dimensionallyarranged in the pixel array unit 11 are shown as a typical example. Inthe pixel array unit 11, the plurality of pixels 100 aretwo-dimensionally arranged in a Bayer pattern. Since each of the pixels100 has a 2PD structure, the pixel 100 can be used for both a pixel foracquiring an image and a pixel for detecting a phase difference.

Further, in FIG. 9 , i-rows and j-columns of the pixels 100 arranged inthe pixel array unit 11 are represented by pixel 100-ij. Note that thisrepresentation applies to other embodiments to be described later.

In the pixel array unit 11, each of the pixels 100 is a square unitpixel having the 2PD structure, and the pixels 100 are physicallyseparated in a silicon layer (semiconductor layer) by an inter-pixelseparation unit 115 arranged in a square lattice.

Note that with respect to G pixels 100 among the pixels 100 arranged inthe pixel array unit 11, a part of the inter-pixel separation unit 115is formed to protrude toward the center of the corresponding pixel 100in a projecting shape. In the following description, this protrudingportion in a projecting shape will be represented as projection portion115P.

For example, assuming that the upper left pixel 100 in the pixelarrangement in four rows and four columns in the pixel array unit 11shown in FIG. 9 is a pixel 100-11, the G pixels 100 for which theprojection portion 115P is formed are a G pixel 100-12, a G pixel100-14, a G pixel 100-21, a G pixel 100-23, a G pixel 100-32, a G pixel100-34, a G pixel 100-41, and a G pixel 100-43.

Specifically, in these G pixels 100, a part of the inter-pixelseparation unit 115 protrudes toward the center of the corresponding Gpixel 100 in a projecting shape to form the projection portion 115P.Note that as shown in FIG. 10 , the area in which the projection portion115P is formed corresponds to the P-type areas A1 and A2 in which thecontribution of isolation between the photoelectric conversion devicesis low in FIG. 8 .

Since the destination of charges generated in the P-type areas isdivided by forming the projection portion 115P that projects in aprojecting shape from the inter-pixel separation unit 115 in two areascorresponding to the P-type areas A1 and A2, it is possible to achieveimprovement in the accuracy of phase difference detection whilesuppressing reduction of the sensitivity or increase in color mixture.

Further, since the G pixel 100 has the 2PD structure, a photoelectricconversion area of a photoelectric conversion device 113A and aphotoelectric conversion area of a photoelectric conversion device 113Bare formed in a silicon layer. These photoelectric conversion areas areseparated by an impurity in the silicon layer as shown by dotted linesin the column direction in FIG. 9 . That is, a physical separation unit(inter-device separation unit 816 in FIG. 5 ) is not formed at thecenter of the G pixel 100 that performs pupil-division, and thephotoelectric conversion areas are separated by the impuritydistribution in the silicon layer.

An X1-X1′ cross section in the plan view of FIG. 9 can be represented bya cross-sectional view shown in FIG. 11 . Note that also in thisexample, assuming that the upper left pixel 100 in the pixel arrangementin four rows and four columns is the pixel 100-11, the pixels 100 shownin the X1-X1′ cross section are four pixels of the G pixel 100-41, a Bpixel 100-42, the G pixel 100-43, and a B pixel 100-44.

In FIG. 11 , the G pixel 100-41 has the 2PD structure including thephotoelectric conversion device 113A and the photoelectric conversiondevice 113B. In the photoelectric conversion device 113A, chargescorresponding to light of G components are generated from light that iscondensed by an on-chip lens 111 and transmitted through a G colorfilter 112. Further, in the photoelectric conversion device 113B,charges corresponding to light of G components are generated, similarlyto the photoelectric conversion device 113A.

In the G pixel 100-43, charges corresponding to light of G componentsare generated by the photoelectric conversion device 113A and thephotoelectric conversion device 113B, similarly to the G pixel 100-41.Further, in the B pixel 100-42 and the B pixel 100-44, chargescorresponding to light of B components are generated by thephotoelectric conversion device 113A and the photoelectric conversiondevice 113B.

The charges generated by the photoelectric conversion device 113A andthe photoelectric conversion device 113B in each pixel 100 in this wayare read via the transfer gate 151A and the transfer gate 151B, and usedas information regarding phase difference detection.

Note that each of the pixels 100-41 to 100-44 is a square unit pixelhaving the 2PD structure, and light is blocked between the adjacentpixels by an inter-pixel light blocking unit 114 arranged in a squarelattice. The inter-pixel light blocking unit 114 is formed of a materialsuch as metals including tungsten (W) and aluminum (Al), and arranged inthe area between the on-chip lens 111 and the silicon layer in which aphotoelectric conversion area is formed.

Further, in the pixels 100-41 to 100-44, the adjacent pixels in thesilicon layer are physically separated by the inter-pixel separationunit 115 arranged in a square lattice. Specifically, in this example,for example, the inter-pixel separation unit 115 is formed by embedding,from the surface of the light incident side (light incident surface,e.g., back side), a material such as an oxidized film and a metal in atrench formed in a square lattice corresponding to the shape of thesquare unit pixel in the silicon layer in which a photoelectricconversion area is formed, by using a DTI (Deep trench Isolation)technology.

In the G pixel 100-41 and the G pixel 100-43, the projection portion115P is formed between the photoelectric conversion device 113A and thephotoelectric conversion device 113B. Specifically, in the G pixel100-41 and the G pixel 100-43 shown in FIG. 11 , a part of theinter-pixel separation unit 115 protrudes toward the center of thecorresponding G pixel 100 in a projecting shape to form the projectionportion 115P.

Further, an X2-X2′ cross section in the plan view shown in FIG. 9 can berepresented by a cross-sectional view shown in FIG. 12 . Note that inFIG. 12 , the pixels shown in the X2-X2′ cross section are the G pixel100-41, the B pixel 100-42, the G pixel 100-43, and the B pixel 100-44,similarly to FIG. 11 .

Since the X2-X2′ cross section is a cross section including the centerof the G pixel 100, it does not include no projection portion 115P thatprotrudes toward the center of the corresponding G pixel 100 in aprojecting shape. Specifically, in the G pixel 100-41 and the G pixel100-43 shown in FIG. 12 , no projection portion 115P is formed betweenthe photoelectric conversion device 113A and the photoelectricconversion device 113B.

Further, a Y-Y′ cross section in the plan view shown in FIG. 9 can berepresented by a cross-sectional view shown in FIG. 13 . Note thatassuming that the upper left pixel 100 in the pixel arrangement in fourrows and four columns is the pixel 100-11 also in this case, the pixelsshown in the Y-Y′ cross section are four pixels of the G pixel 100-12, aB pixel 100-22, the G pixel 100-32, and the B pixel 100-42.

In FIG. 13 , in the G pixel 100-12 and the G pixel 100-32, a part of theinter-pixel separation unit 115 protrudes toward the center of thecorresponding G pixel 100 in a projecting shape to form the projectionportion 115P. Note that in the projection portion 115P shown in FIG. 13, the depth of the projection portion 115P differs for each protrudingpart (depth is not uniform).

Specifically, when viewed in the plan view shown in FIG. 9 , it can beregarded that the projection portion 115P is formed in a T shape withrespect to the inter-pixel separation unit 115. However, as shown inFIG. 13 , the root part of the projection portion 115P has a depthsimilar to that of the inter-pixel separation unit 115, and the depth ofthe projection portion 115P is gradually reduced as it is closer to thetip thereof.

As described above, in the G pixel 100, a part of the inter-pixelseparation unit 115 protrudes toward the center of the corresponding Gpixel 100 to form the projection portion 115P. However, as shown in FIG.11 to FIG. 13 , the existence or non-existence of the projection portion115P or the shape (depth) thereof differs depending on the cut of thecross section.

In other words, in the case where the projection portion 115P of theinter-pixel separation unit 115 is formed in the pixel 100 having the2PD structure, a first cross section (e.g., the cross section shown inFIG. 11 ) including no center of the pixel 100 includes the crosssection of the projection portion 115P between the two photoelectricconversion areas, but a second cross section (e.g., the cross sectionshown in FIG. 12 ) including the center of the pixel 100 includes nocross section of the projection portion 115P between the twophotoelectric conversion areas.

(Structure of Pixel in First Embodiment)

FIG. 14 is a three-dimensional diagram showing the three-dimensionalstructure of the pixel 100 in the first embodiment.

In FIG. 14 , an arbitrary pixel 100 (e.g., G pixel 100 in which theprojection portion 115P is formed) among the plurality of pixels 100two-dimensionally arranged in the pixel array unit 11 is shown. In thepixel array unit 11, the inter-pixel light blocking unit 114 and theinter-pixel separation unit 115 are formed in a square lattice betweenadjacent pixels.

The inter-pixel light blocking unit 114 is formed of a metal such astungsten (W) and aluminum (Al) in a square lattice and blocks lightbetween adjacent pixels. Further, the inter-pixel separation unit 115 isformed of an oxidized film, metal, or the like embedded in a trench in asquare lattice, which is formed in a silicon layer, and physicallyseparates adjacent pixels.

In the first embodiment, a part of the inter-pixel separation unit 115out of the inter-pixel light blocking unit 114 formed in in a squarelattice and the inter-pixel separation unit 115 formed in in a squarelattice protrudes, in a projecting shape, toward the center of thesquare unit pixel 100 having the 2PD structure to form the projectionportion 115P.

As the material of the projection portion 115P, the same material asthat of the inter-pixel separation unit 115 or a different material maybe used. For example, in the case where the inter-pixel separation unit115 is formed of an oxidized film, also the projection portion 115P maybe formed of an oxidized film. Further, for example, in the case wherethe inter-pixel separation unit 115 is formed of a metal, the projectionportion 115P may be formed of an oxidized film.

As described above, the projection portions 115P formed at two placeswith respect to the inter-pixel separation unit 115 in the pixel 100 areformed in the areas where the contribution of isolation is low in thesilicon layer. By forming the projection portion 115P in such areas, itis possible to achieve improvement in the accuracy of phase differencedetection while suppressing reduction of the sensitivity or increase incolor mixture.

Note that although detailed content will be described later withreference to FIG. 22 and FIG. 23 , immediately below the on-chip lens111, for example, a protruding length of the projection portion 115P canbe determined depending on a focused spot diameter of the on-chip lens111 so that physical isolation (silicon isolation) by the projectionportion 115P is not made.

The first embodiment has been described heretofore.

(2) Second Embodiment

(Structure of Pixel in Second Embodiment)

FIG. 15 is a three-dimensional diagram showing a three-dimensionalstructure of the pixel 100 in a second embodiment.

In FIG. 15 , an arbitrary pixel 100 among the plurality of pixels 100two-dimensionally arranged in the pixel array unit 11 is illustrated,similarly to the above-mentioned FIG. 14 . In the pixel array unit 11,between adjacent pixels, the inter-pixel light blocking unit 114 and theinter-pixel separation unit 115 are formed in a square lattice.

In the second embodiment, a part of the inter-pixel light blocking unit114 out of the inter-pixel light blocking unit 114 formed in in a squarelattice and the inter-pixel separation unit 115 formed in in a squarelattice protrudes, in a projecting shape, toward the center of thesquare unit pixel 100 having the 2PD structure to form a projectionportion 114P.

Note that as the material of the projection portion 114P, the samematerial as that of the inter-pixel light blocking unit 114 or adifferent material may be used.

As described above, although the case where the projection portion 115Pis formed with respect to the inter-pixel separation unit 115 has beendescribed in the above-mentioned first embodiment, the projectionportion 114P is formed with respect to the inter-pixel light blockingunit 114 in the second embodiment.

Specifically, the projection portions 114P formed at two places withrespect to the inter-pixel light blocking unit 114 in the pixel 100 areformed in the areas where the contribution of isolation is low in thesilicon layer. By forming the projection portion 114P in such areas, itis possible to achieve improvement in the accuracy of phase differencedetection while suppressing reduction of the sensitivity or increase incolor mixture.

Note that although detailed content will be described later withreference to FIG. 22 and FIG. 23 , for example, a protruding length ofthe projection portion 114P can be determined depending on a focusedspot diameter of the on-chip lens 111.

The second embodiment has been described heretofore.

(3) Third Embodiment

(Structure of Pixel in Third Embodiment)

FIG. 16 is a three-dimensional diagram showing a three-dimensionalstructure of the pixel 100 in a third embodiment.

In FIG. 16 , an arbitrary pixel 100 among the plurality of pixels 100two-dimensionally arranged in the pixel array unit 11 is illustrated,similarly to the above-mentioned FIG. 14 and FIG. 15 . In the pixelarray unit 11, between adjacent pixels, the inter-pixel light blockingunit 114 and the inter-pixel separation unit 115 are formed in a squarelattice.

In the third embodiment, a part of the inter-pixel light blocking unit114 formed in in a square lattice and a part of the inter-pixelseparation unit 115 formed in in a square lattice protrude, in aprojecting shape, toward the center of the square unit pixel 100 havingthe 2PD structure to form the projection portion 114P and the projectionportion 115P, respectively.

Note that as the material of the projection portion 114P, the samematerial as that of the inter-pixel light blocking unit 114 or adifferent material may be used. Further, as the material of theprojection portion 115P, the same material as that of the inter-pixelseparation unit 115 or a different material may be used

As described above, although the case where the projection portion 115Pis formed with respect to the inter-pixel separation unit 115 has beendescribed in the above-mentioned first embodiment and the case where theprojection portion 114P is formed with respect to the inter-pixel lightblocking unit 114 has been described in the second embodiment, theprojection portion 114P and the projection portion 115P are respectivelyformed with respect to the inter-pixel light blocking unit 114 and theinter-pixel separation unit 115 in the third embodiment.

Specifically, the projection portions 114P formed at two places withrespect to the inter-pixel light blocking unit 114 in the pixel 100 areformed in the areas where the contribution of isolation is low in thesilicon layer. Further, the projection portions 115P formed at twoplaces with respect to the inter-pixel separation unit 115 in the pixel100 are formed in the areas where the contribution of isolation is lowin the silicon layer. By forming the projection portion 114P and theprojection portion 115P in such areas, it is possible to achieveimprovement in the accuracy of phase difference detection whilesuppressing reduction of the sensitivity or increase in color mixture.

Note that although detailed content will be described later withreference to FIG. 22 and FIG. 23 , for example, a protruding length ofthe projection portion 114P and a protruding length of the projectionportion 115P can be determined depending on a focused spot diameter ofthe on-chip lens 111.

The third embodiment has been described heretofore.

(4) Fourth Embodiment

(Structure in which Projection Portion is Formed Only with Respect to GPixel)

FIG. 17 is a plan view showing a structure of the pixel 100 in a fourthembodiment.

In FIG. 17 , the pixels 100 in four rows and four columns arranged in apartial area among the plurality of pixels 100 two-dimensionallyarranged in the pixel array unit 11 are illustrated as a typicalexample. Among the pixels 100 arranged in a Bayer array, the projectionportion 115P is formed with respect to the inter-pixel separation unit115 only in the G pixel 100.

For example, assuming that the upper left pixel 100 in the pixelarrangement in four rows and four columns shown in FIG. 17 is the pixel100-11, the G pixels 100 in which the projection portion 115P is formedare the G pixel 100-12, the G pixel 100-14, the G pixel 100-21, the Gpixel 100-23, the G pixel 100-32, the G pixel 100-34, the G pixel100-41, and the G pixel 100-43.

Now, assumption is made that when comparing information acquired from anoutput of the G pixel 100 and information acquired from outputs of the Rpixel 100 and the B pixel 100, the amount of information acquired fromthe output of the G pixel 100 is the largest, e.g., the informationacquired from the output of the G pixel 100 is dominant when acquiringinformation regarding phase difference detection. In this case, thestructure in which the projection portion 115P is formed only in the Gpixel 100 as shown in FIG. 17 can be employed.

Note that the structure in which the projection portion 115P is formedwith respect to the inter-pixel separation unit 115 only in the G pixel100 shown in FIG. 17 is similar to the above-mentioned structure shownin FIG. 9 . Further, a photoelectric conversion area of thephotoelectric conversion device 113A and a photoelectric conversion areaof the photoelectric conversion device 113B in the pixel 100 areseparated by an impurity in a silicon layer as shown by dotted lines inthe column direction in FIG. 17 .

Further, although the case where the projection portion 115P is formedwith respect to the inter-pixel separation unit 115 corresponding to theabove-mentioned first embodiment has been described in FIG. 17 , theprojection portion 114P may be formed with respect to the inter-pixellight blocking unit 114 only in the G pixel 100 corresponding to theabove-mentioned second embodiment. Further, projection portions may beformed with respect to the inter-pixel light blocking unit 114 and theinter-pixel separation unit 115 only in the G pixel 100 corresponding tothe above-mentioned third embodiment.

(Structure in which Projection Portions Are Formed in All Pixels)

FIG. 18 is a plan view showing a first modified example of the structureof the pixel 100 in the fourth embodiment.

In FIG. 18 , arbitrary pixels 100 in four rows and four columns amongthe plurality of pixels 100 arranged in a Bayer array in the pixel arrayunit 11 are illustrated. In all of the pixels 100, the projectionportion 115P is formed with respect to the inter-pixel separation unit115.

For example, assuming the upper left pixel 100 in the pixel arrangementin four rows and four columns shown in FIG. 18 is the pixel 100-11, thepixels 100 in which the projection portion 115P is formed are the Rpixels 100 (100-11, 100-13, 100-31, and 100-33), the G pixels 100(100-12, 100-14, 100-21, 100-23, 100-32, 100-34, 100-41, and 100-43),and the B pixels 100 (100-22, 100-24, 100-42, and 100-44).

Note that in the case where the projection portion 115P is formed in theR pixel 100, the G pixel 100, and the B pixel 100, since informationregarding phase difference detection can be acquired from outputs of allthe pixels 100, a configuration in which the projection portion 115P isformed in all the pixels 100 as shown in FIG. 18 can be employed, forexample, when it is desired to acquire information regarding phasedifference detection from all the pixels 100.

Further, although the case where the projection portion 115P is formedwith respect to the inter-pixel separation unit 115 corresponding to theabove-mentioned first embodiment has been described in FIG. 18 , theprojection portion 114P may be formed with respect to the inter-pixellight blocking unit 114 in all the G pixel 100 corresponding to theabove-mentioned second embodiment. Further, projection portions may beformed with respect to the inter-pixel light blocking unit 114 and theinter-pixel separation unit 115 in all the G pixel 100 corresponding tothe above-mentioned third embodiment.

(Structure in which Projection Portion is Formed Only in R Pixel)

FIG. 19 is a plan view showing a second modified example of thestructure of the pixel 100 in the fourth embodiment.

In FIG. 19 , arbitrary pixels 100 in four rows and four columns amongthe plurality of pixels 100 arranged in a Bayer array in the pixel arrayunit 11 are illustrated. Only in the R pixel 100, the projection portion115P is formed with respect to the inter-pixel separation unit 115.

For example, assuming the upper left pixel 100 in the pixel arrangementin four rows and four columns shown in FIG. 19 is the pixel 100-11, theR pixels 100 in which the projection portion 115P is formed are the Rpixel 100-11, the R pixel 100-13, the R pixel 100-31, and the R pixel100-33.

Note that although the case where the projection portion 115P is formedwith respect to the inter-pixel separation unit 115 corresponding to theabove-mentioned first embodiment has been described in FIG. 19 , theprojection portion 114P may be formed with respect to the inter-pixellight blocking unit 114 only in the R pixel 100 corresponding to theabove-mentioned second embodiment. Further, projection portions may beformed with respect to the inter-pixel light blocking unit 114 and theinter-pixel separation unit 115 only in the R pixel 100 corresponding tothe above-mentioned third embodiment.

(Structure in which Projection Portion is Formed Only in B Pixel)

FIG. 20 is a plan view showing a third modified example of the structureof the pixel 100 in the fourth embodiment.

In FIG. 20 , arbitrary pixels 100 in four rows and four columns amongthe plurality of pixels 100 arranged in a Bayer array in the pixel arrayunit 11 are illustrated. Only in the B pixel 100, the projection portion115P is formed with respect to the inter-pixel separation unit 115.

For example, assuming the upper left pixel 100 in the pixel arrangementin four rows and four columns shown in FIG. 20 is the pixel 100-11, theB pixels 100 in which the projection portion 115P is formed are the Bpixel 100-22, the B pixel 100-24, the B pixel 100-42, and the B pixel100-44.

Note that although the case where the projection portion 115P is formedwith respect to the inter-pixel separation unit 115 corresponding to theabove-mentioned first embodiment has been described in FIG. 20 , theprojection portion 114P may be formed with respect to the inter-pixellight blocking unit 114 only in the B pixel 100 corresponding to theabove-mentioned second embodiment. Further, projection portions may beformed with respect to the inter-pixel light blocking unit 114 and theinter-pixel separation unit 115 only in the B pixel 100 corresponding tothe above-mentioned third embodiment.

(Structure in which Projection Portions are Formed Only in G and BPixels)

FIG. 21 is a plan view showing a fourth modified example of thestructure of the pixel 100 in the fourth embodiment.

In FIG. 21 , arbitrary pixels 100 in four rows and four columns amongthe plurality of pixels 100 arranged in a Bayer array in the pixel arrayunit 11 are illustrated. Only in the G pixel 100 and the B pixel 100,the projection portion 115P is formed with respect to the inter-pixelseparation unit 115.

For example, assuming the upper left pixel 100 in the pixel arrangementin four rows and four columns shown in FIG. 21 is the pixel 100-11, thepixels 100 in which the projection portion 115P is formed are the Gpixels 100 (100-12, 100-14, 100-21, 100-23, 100-32, 100-34, 100-41, and100-43) and the B pixels 100 (100-22, 100-24, 100-42, and 100-44).

Note that although the case where the projection portion 115P is formedwith respect to the inter-pixel separation unit 115 corresponding to theabove-mentioned first embodiment has been described in FIG. 21 , theprojection portion 114P may be formed with respect to the inter-pixellight blocking unit 114 only in the G pixel 100 and the B pixel 100corresponding to the above-mentioned second embodiment. Further,projection portions may be formed with respect to the inter-pixel lightblocking unit 114 and the inter-pixel separation unit 115 only in the Gpixel 100 and the B pixel 100 corresponding to the above-mentioned thirdembodiment.

Further, although a combination of the G pixel 100 and the B pixel 100is illustrated as a combination of the pixels 100 in which theprojection portion 115P is formed in this example, the pattern of thecombination of the pixels 100 in which the projection portion 115P isformed can be arbitrarily determined, e.g., a combination of the R pixel100 and the G pixel 100 and a combination of the R pixel 100 and the Bpixel 100.

The fourth embodiment has been described heretofore.

(5) Fifth Embodiment

(Determination of Length of Projection Portion)

FIG. 22 is a plan view showing a structure of the pixel 100 in a fifthembodiment.

In FIG. 22 , in the pixel 100, a part of the inter-pixel separation unit115 arranged in a square lattice protrudes toward the center of thepixel 100 in a projecting shape to form the projection portion 115P. Alength of a protruding part of the projection portion 115P (hereinafter,referred to also as the projecting length) can be an arbitrary length.However, for example, the length may be determined as follows.

Specifically, for example, when the diameter of a focused spot S on thelight incident surface in the silicon (Si) layer in which thephotoelectric conversion devices 113A and 113B are formed is increasedfor some reason in the case where the height of the on-chip lens 111 inthe optical axis direction (stacking direction) is changed, there is aneed to reduce the projecting length to prevent light from scattering.

Since the projecting length of the projection portion 115P has acorrelation with the diameter of the focused spot S of the on-chip lens111 as described above, the projecting length of the projection portion115P can be determined depending on the diameter of the focused spot Sof the on-chip lens 111.

For example, the inventors of the present technology have found, byperforming detailed simulation, that when the projecting length of theprojection portion 115P is represented by L1 and a length of a side of apitch of the on-chip lens 111 is represented by L2, L1 is favorablywithin the range of one seventh to one fourth a length of L2.

In FIG. 23 , a structure in which the position of the on-chip lens 111is high with respect to the light incident surface of the silicon layeris represented in a cross-sectional view shown in A of FIG. 23 , and astructure in which the position of the on-chip lens 111 is low withrespect to the light incident surface of the silicon layer isrepresented in a cross-sectional view shown in B of FIG. 23 . Note thatthe cross-sectional view shown in FIG. 23 corresponds to the Y-Y′ crosssection in the plan view shown in FIG. 9 .

In A of FIG. 23 , the height of the on-chip lens 111 in the optical axisdirection with respect to the light incident surface of the siliconlayer is represented by H_(A), and a focused spot on the light incidentsurface by an incident light IL_(A) is represented by S_(A). Meanwhile,in B of FIG. 23 , the height of the on-chip lens 111 in the optical axisdirection with respect to the light incident surface of the siliconlayer is represented by H_(B), and a focused spot on the light incidentsurface by an incident light IL_(B) is represented by S_(B).

When comparing the height of the on-chip lens 111 between A of FIG. 23and B of FIG. 23 , a relationship of H_(A)>H_(B) is established. Then,since height of the on-chip lens 111 has such a relationship, whencomparing the diameter of the focused spot between A of FIG. 23 and B ofFIG. 23 , a relationship of S_(A)<S_(B) is established.

On the basis of such a relationship, a projecting length L1 _(A) of theprojection portion 115P is adjusted depending on the diameter of thefocused spot S_(A) in A of FIG. 23 , and a projecting length L1 _(B) ofthe projection portion 115P is adjusted depending on the diameter of thefocused spot S_(B) in B of FIG. 23 . Note that since there is a need toreduce the projecting length to prevent light from scattering as thediameter of the focused spot is increased as described above, arelationship of L1 _(A)>L1 _(B) is established in accordance with therelationship of S_(A)<S_(B).

Note that although a method of determining the projecting length of theprojection portion 115P of the inter-pixel separation unit 115 dependingon the diameter of the focused spot S of the on-chip lens 111 has beendescribed heretofore, also a length of a protruding part of theprojection portion 114P of the inter-pixel light blocking unit 114(projecting length) can be determined depending on the diameter of thefocused spot S of the on-chip lens 111, similarly.

Further, the above-mentioned method of determining the projecting lengthof the projection portion 115P is an example, and the projecting lengthof the projection portion 115P may be determined by a method other thanthe method using the diameter of the focused spot S of the on-chip lens111.

The fifth embodiment has been described heretofore.

(6) Sixth Embodiment

(Structure in which Length of Projection Portion is Changed for EachPixel)

FIG. 24 is a plan view showing a structure of the pixel 100 in a sixthembodiment.

In FIG. 24 , arbitrary pixels 100 in four rows and four columns amongthe plurality of pixels 100 arranged in a Bayer array in the pixel arrayunit 11 are illustrated. In all the pixels 100, the projection portion115P is formed with respect to the inter-pixel separation unit 115.

For example, assuming the upper left pixel 100 in the pixel arrangementin four rows and four columns shown in FIG. 24 is the pixel 100-11, thepixels 100 in which the projection portion 115P is formed are the Rpixels 100 (100-11, 100-13, 100-31, and 100-33), the G pixels 100(100-12, 100-14, 100-21, 100-23, 100-32, 100-34, 100-41, and 100-43),and the B pixels 100 (100-22, 100-24, 100-42, and 100-44).

Note that in FIG. 24 , the projecting length of the projection portion115P differs for each color pixel of the R pixel 100, the G pixel 100,and the B pixel 100. Specifically, in FIG. 24 , the projecting length ofthe projection portion 115P formed in the R pixel 100 is shorter thanthe projecting length of the projection portion 115P formed in the Gpixel 100 while the projecting length of the projection portion 115Pformed in the B pixel 100 is longer than the projecting length of theprojection portion 115P formed in the G pixel 100.

Specifically, when the projecting length of the projection portion 115Pof the R pixel 100 is represented by L1 _(B), the projecting length ofthe projection portion 115P of the G pixel 100 is represented by L1_(G), and the projecting length of the projection portion 115P of the Bpixel 100 is represented by L1 _(B), a relationship of L1 _(B)>L1_(G)>L1 _(B) is established.

For example, since the red (R) wavelength is longer than the green (G)or blue (B) wavelength, scattering of light is highly likely to occur inthe R pixel 100 as compared with the G pixel 100 or the B pixel 100. Inthis regard, countermeasures that make the projecting length of theprojection portion 115P of the R pixel 100 shorter than that of the Gpixel 100 or the B pixel 100 can be considered.

Note that although the case where the projecting length of theprojection portion 115P of the inter-pixel separation unit 115 ischanged for each pixel 100 has been described, also a length of aprotruding part (projecting length) of the projection portion 114P ofthe inter-pixel light blocking unit 114 may be changed for each pixel100, similarly.

Further, although the case where the projecting length of the projectionportion 115P in all the R pixel 100, the G pixel 100, and the B pixel100 is changed has been described above, for example, a combination ofthe pixels 100 in which the projecting length of the projection portion115P is changed can be arbitrarily determined, e.g., the projectinglengths of the projection portions 115P of the G pixel 100 and the Bpixel 100 can be the same and only the projecting length of theprojection portion 115P of the R pixel 100 can be reduced. Further, theprojecting lengths of the projection portions 115P of not only thepixels 100 of different colors but also of the pixels 100 of the samecolor may be changed.

The sixth embodiment has been described heretofore.

(7) Seventh Embodiment

(Structure in which On-Chip Lens Having Elliptical Shape in RowDirection is Used)

FIG. 25 is a plan view showing a structure of the pixel 100 in a seventhembodiment.

In FIG. 25 , arbitrary pixels 100 in four rows and four columns amongthe plurality of pixels 100 two-dimensionally arranged in the pixelarray unit 11 are illustrated. Note that in the pixel arrangement infour rows and four columns shown in FIG. 25 , each of the pixels 100 hasa structure including one photoelectric conversion device 113.Specifically, in FIG. 25 , each of the pixels 100 has not the 2PDstructure but, so to speak, a 1PD structure. Here, in order todistinguish from the above-mentioned pixel 100 having the 2PD structure,the pixel 100 having the 1PD structure will be expressed as the pixel100 (1PD).

For example, assuming that the upper left pixel 100 (1PD) in the pixelarrangement in four rows and four columns shown in FIG. 25 is the pixel100-11 (1PD), an elliptical on-chip lens 111E is formed with respect tothe G pixel 100-21 (1PD) and the G pixel 100-22 (1PD) arranged in thesame row. Note that although not shown, in the pixels 100 (1PD) otherthan the G pixel 100-21 (1PD) and the G pixel 100-22 (1PD), onephotoelectric conversion device 113 is formed with respect to oneon-chip lens 111.

Specifically, in the pixel including the two pixels (G pixel 100-21(1PD), 100-22 (1PD)) arranged in the same row, a structure in which thephotoelectric conversion device 113 of the G pixel 100-21 (1PD) and thephotoelectric conversion device 113 of the G pixel 100-22 (1PD) areformed with respect to one on-chip lens 111E is provided. Then, phasedifference detection is performed by using outputs of the photoelectricconversion device 113 of the G pixel 100-21 (1PD) and the photoelectricconversion device 113 of the G pixel 100-22 (1PD) arranged in the samerow.

Further, in this example, the projection portion 115P formed withrespect to the inter-pixel separation unit 115 is formed between the Gpixel 100-21 (1PD) and the G pixel 100-22 (1PD) while the ellipticalon-chip lens 111E has a structure covering the G pixel 100-21 (1PD) andthe G pixel 100-22 (1PD) in the row direction.

Also in this case, a part of the inter-pixel separation unit 115protrudes, in a projecting shape, toward the center of the areaincluding the G pixel 100-21 (1PD) and the G pixel 100-22 (1PD) to formthe projection portion 115P at two places. Further, the projectinglength of the projection portion 115P can be determined depending on thediameter of the focused spot of the elliptical on-chip lens 111E, forexample.

(Structure Using On-Chip Lens Having Elliptical Shape in ColumnDirection)

FIG. 26 is a plan view showing a modified example of the structure ofthe pixel 100 in the seventh embodiment.

In FIG. 26 , arbitrary pixels 100 in four rows and four columns amongthe plurality of pixels 100 two-dimensionally arranged in the pixelarray unit 11 are illustrated. Note that the pixels 100 in the pixelarrangement in four rows and four columns shown in FIG. 26 each have the1PD structure, similarly to the above-mentioned pixels 100 shown in FIG.25 . The pixel 100 having the 1PD structure will be expressed as thepixel 100 (1PD).

Here, for example, in the pixel arrangement in four rows and fourcolumns shown in FIG. 26 , the elliptical on-chip lens 111E is formedwith respect to the G pixel 100-12 (1PD) and the G pixel 100-22 (1PD)arranged in the same column. Note that although not shown, in the pixels100 (1PD) other than the G pixel 100-12 (1PD) and the G pixel 100-22(1PD), one photoelectric conversion device 113 is formed with respect toone on-chip lens 111.

Specifically, in the pixel including the two pixels (G pixel 100-12(1PD), 100-22 (1PD)) arranged in the same row, a structure in which thephotoelectric conversion device 113 of the G pixel 100-12 (1PD) and thephotoelectric conversion device 113 of the G pixel 100-22 (1PD) areformed with respect to one on-chip lens 111E is provided. Then, phasedifference detection is performed by using outputs of the photoelectricconversion device 113 of the G pixel 100-12 (1PD) and the photoelectricconversion device 113 of the G pixel 100-22 (1PD) arranged in the samecolumn.

Further, in this example, the projection portion 115P formed withrespect to the inter-pixel separation unit 115 is formed between the Gpixel 100-12 (1PD) and the G pixel 100-22 (1PD) while the ellipticalon-chip lens 111E has a structure covering the G pixel 100-12 (1PD) andthe G pixel 100-22 (1PD) in the column direction.

Also in this case, a part of the inter-pixel separation unit 115protrudes, in a projecting shape, toward the center of the areaincluding the G pixel 100-12 (1PD) and the G pixel 100-22 (1PD) to formthe projection portion 115P at two places. Further, the projectinglength of the projection portion 115P can be determined depending on thediameter of the focused spot of the elliptical on-chip lens 111E, forexample.

Note that although the case where the projection portion 115P of theinter-pixel separation unit 115 is formed with respect to the two pixels100 (1PD) arranged in the same row or the same column for eachelliptical on-chip lens 111E has been described, the projection portion114P of the inter-pixel light blocking unit 114 may be formed.

Further, although the case where the two G pixels 100 (1PD) are arrangedwith respect to the elliptical on-chip lens 111E are arranged has beendescribed above, instead of the G pixels 100 (1PD), the R pixels 100(1PD) or the B pixels 100 (1PD) may be arranged with respect to theelliptical on-chip lens 111E.

The seventh embodiment has been described heretofore.

(8) Eight Embodiment

(Structure in which Plurality of Pixels are Arranged with Respect toSingle On-Chip Lens)

FIG. 27 is a plan view showing a structure of the pixel 100 in an eighthembodiment.

In FIG. 27 , arbitrary pixels 100 in four rows and four columns amongthe plurality of pixels 100 two-dimensionally arranged in the pixelarray unit 11 are illustrated. Note that the pixels 100 in the pixelarrangement in four rows and four columns shown in FIG. 27 each have the1PD structure, similarly to the above-mentioned pixels 100 shown in FIG.25 and FIG. 26 . The pixel 100 having the 1PD structure will beexpressed as the pixel 100 (1PD).

In the pixel arrangement in four rows and four columns shown in FIG. 27, the circular on-chip lens 111 is formed for each four pixels 100 (1PD)of the same color.

For example, assuming that the upper left pixel 100 (1PD) in the pixelarrangement in four rows and four columns shown in FIG. 27 is the pixel100-11 (1PD), one on-chip lens 111-11 is formed with respect to thepixel including the four R pixels 100 (1PD) of the R pixel 100-11 (1PD),the R pixel 100-12 (1PD), the R pixel 100-21 (1PD), and the R pixel100-22 (1PD).

Further, a part of the inter-pixel separation unit 115 protrudes, in aprojecting shape, toward the center of the area including the four Rpixels 100 (1PD) to form the projection portion 115P at four placeswhile the circular on-chip lens 111-11 has a structure covering the fourR pixels 100 (1PD) (100-11 (1PD), 100-12 (1PD), 100-21 (1PD), and 100-22(1PD)).

In the pixel arrangement shown in FIG. 27 , one on-chip lens 111-12 isformed with respect to the pixel including the four G pixels 100 (1PD)of the G pixel 100-13 (1PD), the G pixel 100-14 (1PD), the G pixel100-23 (1PD), and the G pixel 100-24 (1PD). Further, a part of theinter-pixel separation unit 115 protrudes, in a projecting shape, towardthe center of the area including the four G pixels 100 (1PD) to form theprojection portion 115P at four places while the circular on-chip lens111-12 has a structure covering the four G pixels 100 (1PD) (100-13(1PD), 100-14 (1PD), 100-23 (1PD), and 100-24 (1PD)).

Further, in the pixel arrangement shown in FIG. 27 , one on-chip lens111-21 is formed with respect to the pixel including the four G pixels100 (1PD) of the G pixel 100-31 (1PD), the G pixel 100-32 (1PD), the Gpixel 100-41 (1PD), and the G pixel 100-42 (1PD). Further, a part of theinter-pixel separation unit 115 protrudes, in a projecting shape, towardthe center of the area including the four G pixels 100 (1PD) to form theprojection portion 115P at four places while the circular on-chip lens111-21 has a structure covering the four G pixels 100 (1PD) (100-31(1PD), 100-32 (1PD), 100-41 (1PD), and 100-42 (1PD)).

Further, in the pixel arrangement shown in FIG. 27 , one on-chip lens111-22 is formed with respect to the pixel including the four B pixels100 (1PD) of the B pixel 100-33 (1PD), the B pixel 100-34 (1PD), the Bpixel 100-43 (1PD), and the B pixel 100-44 (1PD). Further, a part of theinter-pixel separation unit 115 protrudes, in a projecting shape, towardthe center of the area including the four G pixels 100 (1PD) to form theprojection portion 115P at four places while the circular on-chip lens111-22 has a structure covering the four B pixels 100 (1PD) (100-33(1PD), 100-34 (1PD), 100-43 (1PD), and 100-44 (1PD)).

As described above, in the pixel arrangement shown in FIG. 27 , astructure in which the photoelectric conversion devices 113 of the fourpixels 100 (1PD) are formed with respect to the pixel (including thefour pixels 100 (1PD)) in which one on-chip lens 111 and one colorfilter 112 are provided is provided. Then, in this example, phasedifference detection is performed by using outputs of the respectivephotoelectric conversion devices 113 of the four pixels 100 (1PD)sharing the one on-chip lens ill and the one color filter 112. Since thepixels 100 (1PD) in two rows and two columns are arranged with respectto the one on-chip lens 111 in this example, for example, it is possibleto acquire information regarding phase difference detection in bothdirections of the row direction and the column direction.

Note that although the case where the projection portion 115P of theinter-pixel separation unit 115 is formed with respect to the pixels 100(1PD) in two rows and two columns arranged for each on-chip lens 111 hasbeen described, the projection portion 114P of the inter-pixel lightblocking unit 114 may be formed.

The eighth embodiment has been described heretofore.

(9) Ninth Embodiment

(Plane Layout of Pixel)

FIG. 28 is a diagram showing a plane layout of the pixel 100 in a ninthembodiment.

In FIG. 28 , arbitrary pixels 100 in four rows and four columns amongthe plurality of pixels 100 arranged in a Bayer array in the pixel arrayunit 11 are illustrated. Note that the pixels 100 in the pixelarrangement in four rows and four columns shown in FIG. 28 each have the2PD structure, similarly to the pixels 100 shown in the above-mentionedFIG. 9 or the like.

Further, in FIG. 28 , in the G pixels 100 among the pixels 100 in thepixel arrangement in four rows and four columns, a part of theinter-pixel separation unit 115 protrudes toward the center of the Gpixel 100 in a projecting shape to form the projection portion 115P,similarly to the above-mentioned FIG. 9 or the like. More specifically,as shown in FIG. 29 , the projection portion 115P of the inter-pixelseparation unit 115 is formed in the areas corresponding to the P-typeareas A1 and A2 in which the contribution of isolation between thephotoelectric conversion devices is low in the above-mentioned FIG. 8 .

An X-X′ cross section in the plan view shown in FIG. 28 can berepresented by a cross-sectional view shown in FIG. 30. Note thatassuming that the upper left pixel 100 in the pixel arrangement in fourrows and four columns is the pixel 100-11, the pixels 100 shown in theX-X′ cross section are four pixels of the G pixel 100-41, the B pixel100-42, the G pixel 100-43, and the B pixel 100-44.

The structure shown in the cross-sectional view of FIG. 30 is basicallysimilar to that in the above-mentioned cross-sectional view of FIG. 11 .However, the method (manufacturing process) of processing theinter-pixel separation unit 115 differs.

Specifically, in the above-mentioned FIG. 11 , the inter-pixelseparation unit 115 is formed by forming a trench from the surface onthe light incident side (light incident surface) in a silicon layer byusing a DTI technology and embedding the material such as an oxidizedfilm and a metal in the trench. Meanwhile, in FIG. 30 , the inter-pixelseparation unit 115 is formed by forming a trench from the surfaceopposite to the light incident side (surface on the side of the transfergates 151A and 151B, e.g., front side) in a silicon layer and embeddingthe material such as an oxidized film and a metal in the trench.

The ninth embodiment has been described heretofore.

(10) Tenth Embodiment

Meanwhile, in a solid-state imaging device such as a CMOS image sensor,in the case where the inter-device separation between the twophotoelectric conversion devices immediately below the single on-chiplens is realized by implanting impurities by an implantation method(hereinafter, referred to as impurity implantation), it is assumed thatthe following problems will occur. Specifically, it is a problem thatcharges (negative charges, i.e., electrons (carriers)) generated in thevicinity of the silicon interface of the light incident surface (e.g.,back side) where it is difficult to apply an electric field or at a partof the inter-device separation unit where an electric field is weak arenot accumulated in desired right and left photoelectric conversiondevices due to the impurity implantation, and the accuracy of phasedifference detection is reduced.

In view of the above, in the tenth embodiment, as the pixels 200 to betwo-dimensionally arranged in the pixel array unit 11 of the CMOS imagesensor 10 (FIG. 1 ), a structure in which a fixed charge amount on thesilicon interface between the central portion of the right and leftphotoelectric conversion devices and other portions is changed to form apotential gradient from the central portion to the right and leftphotoelectric conversion devices is employed. By employing such asstructure, it is possible to improve the accuracy of phase differencedetection by causing charges (electrons) photoelectrically converted inthe vicinity of the silicon interface to be accumulated in desired rightand left photoelectric conversion devices.

Hereinafter, the structure of the pixel in the tenth embodiment will bedescribed with reference to FIG. 31 to FIG. 42 .

First Example of Structure

FIG. 31 is a cross-sectional view showing a first example of thestructure of the pixel in the tenth embodiment.

In FIG. 31 , the pixel 200 has a 2PD structure, and includes an on-chiplens 211, a color filter 212, photoelectric conversion devices 213A and213B, an inter-pixel light blocking unit 214, and an inter-pixelseparation unit 215.

Note that since in the pixel 200, the on-chip lens 211 to theinter-pixel separation unit 215 respectively correspond to the on-chiplens 111, the color filter 112, the photoelectric conversion devices113A and 113B, the inter-pixel light blocking unit 114, and theinter-pixel separation unit 115 in the pixel 100 (FIG. 11 , etc.) in theabove-mentioned embodiments, description thereof will be omitted asappropriate. However, in the pixel 200 in FIG. 31 , the inter-pixelseparation unit 215 includes an oxide film.

In the pixel 200, the incident light IL condensed by the on-chip lens211 passes through the color filter 212 and is applied to thephotoelectric conversion area in the photoelectric conversion device213A or the photoelectric conversion device 213B.

A of FIG. 31 shows the case where the condensing spot of the incidentlight IL A is shifted to the left side from the central portion of theright and left photoelectric conversion devices 213A and 213B, i.e.,there is a phase difference shift. Meanwhile, B of FIG. 31 shows thecase where the condensing spot of the incident light IL B is at thecenter portion of the right and left photoelectric conversion devices213A and 213B, i.e., there is no phase difference shift.

Here, in the silicon layer (semiconductor layer), the fixed chargeamount on the silicon interface on the light incident side differsbetween the central portion of the right and left photoelectricconversion devices 213A and 213B and the other portions.

Specifically, in the case of comparing a fixed charge amount in acentral area 221 (first area) that is an area of the central portion onthe silicon interface on the light incident side and a fixed chargeamount in a right-and-left area 222 (second area) that is an area (rightand left areas of the central portion) excluding the central portionwith other, the fixed charge amount in the central area 221 is largerthan the fixed charge amount in the right-and-left area 222.

As described above, by changing the fixed charge amounts of the centralarea 221 and the right-and-left area 222 on the silicon interface on thelight incident side to form a potential gradient from the centralportion between the right and left photoelectric conversion devices 213Aand 213B to the right and left photoelectric conversion devices 213A and213B, it is possible to cause the electrons photoelectrically convertedon the silicon interface to be accumulated in the desired right and leftphotoelectric conversion devices 213A and 213B.

For example, in the pixel 200 in A of FIG. 31 , in the case where thereis a phase difference shift as indicated by the incident light IL_(A) inthe figure, since the electrons photoelectrically converted in thevicinity of the silicon interface are accumulated in the desired rightand left photoelectric conversion devices 213A and 213B due to thepotential gradient and the separation ratio is improved, it is possibleto improve the accuracy of phase difference detection.

Second Example of Structure

FIG. 32 is a cross-sectional view showing a second example of thestructure of the pixel in the tenth embodiment.

FIG. 32 shows, in an enlarged manner, an area including the central area221 and the right-and-left area 222 on the silicon interface on thelight incident side, of the cross section of the pixel 200 shown in FIG.31 . As shown in the enlarged view, an insulation layer 230 formed on(the interface layer 220 of) a silicon layer 210 has a structure inwhich a layer including a High-k film 232A and a High-k film 232B isstacked on an oxide film 231 and an oxide film 233.

The High-k film is a high dielectric constant insulation film (highdielectric constant film) formed of a material having a relativedielectric constant higher than that of an insulation film such assilicon dioxide (SiO 2).

Here, in the insulation layer 230, the High-k film 232A is formed on theoxide film 231 so as to correspond to the right-and-left area 222 in theinterface layer 220. Further, in the insulation layer 230, the High-kfilm 232B is formed on the oxide film 231 so as to correspond to thecentral area 221 in the interface layer 220. Note that in the insulationlayer 230, the oxide film 233 is formed as the upper layer of the layerincluding the High-k film 232A and the High-k film 232B.

The High-k film 232A and the High-k film 232B are different highdielectric constant films, and aluminum oxide (Al₂O₃), hafnium oxide(HfO₂), or the like can be used, for example. Further, as the oxide film231 and the oxide film 233, for example, silicon dioxide (SiO₂) can beused.

As described above, in the pixel 200 in FIG. 32 , the insulation layer230 has a structure in which the High-k film 232B is formed in a partcorresponding to the central area 221 that is the central portionbetween the right and left photoelectric conversion devices 213A and213B, which has a large fixed charge amount, and the High-k film 232A isformed in a part corresponding to the right-and-left area 222 excludingthe central portion, which has a low fixed charge amount.

With such a structure, in the pixel 200 in FIG. 32 , in the case wherethere is a phase difference shift as indicated by the incident light ILin the figure, since the electrons photoelectrically converted in thevicinity of the silicon interface are accumulated in the desired rightand left photoelectric conversion devices 213A and 213B, it is possibleto improve the accuracy of phase difference detection.

(Third Example of Structure)

FIG. 33 is a cross-sectional view showing a third example of thestructure of the pixel in the tenth embodiment.

Similarly to FIG. 32 described above, FIG. 33 shows, in an enlargedmanner, an area including the central area 221 and the right-and-leftarea 222 on the silicon interface, of the cross section of the pixel 200shown in FIG. 31 . However, the structure of the cross section of theinsulation layer 230 is different from that in the enlarged view of FIG.32 described above.

That is, the insulation layer 230 in FIG. 33 has a structure in whichthe layer to be formed between the oxide film 231 and the oxide film 233is obtained by stacking a lower layer including only the High-k film232A and an upper layer including the High-k film 232A and the High-kfilm 232B, and the High-k film 232B is embedded in a concave portion ofthe High-k film 232A having a concave shape.

As described above, in the pixel 200 in FIG. 33 , the insulation layer230 has a structure in which the High-k films 232A and 232B (A+B) areformed in a part corresponding to the central area 221 that is thecentral portion between the right and left photoelectric conversiondevices 213A and 213B, which has a large fixed charge amount, and theHigh-k film 232A (A) is formed in a part corresponding to theright-and-left area 222 excluding the central portion, which has a lowfixed charge amount.

In other words, in at least one of the High-k film of the partcorresponding to the central area 221 and the High-k film of the partcorresponding to the right-and-left area 222, two or more different highdielectric constant films are stacked.

With such a configuration, in the pixel 200 in FIG. 33 , in the casewhere there is a phase difference shift as indicated by the incidentlight IL in the figured, the electrons photoelectrically converted inthe vicinity of the silicon interface are accumulated in the desiredright and left photoelectric conversion devices 213A and 213B, it ispossible to improve the accuracy of phase difference detection.

Fourth Example of Structure

FIG. 34 is a cross-sectional view showing a fourth example of thestructure of the pixel in the tenth embodiment.

Similarly to FIG. 32 or the like described above, FIG. 34 shows, in anenlarged manner, an area including the central area 221 and theright-and-left area 222 on the silicon interface, of the cross sectionof the pixel 200 shown in FIG. 31 . However, the structure of the crosssection of the insulation layer 230 is different from that in theenlarged view of FIG. 32 or the like described above.

That is, the insulation layer 230 in FIG. 34 has a structure in whichthe layer to be formed between the oxide film 231 and the oxide film 233is obtained by stacking a lower layer including only the High-k film232A and an upper layer including the High-k film 232B and a High-k film232C. Here, the High-k film 232C is a high dielectric constant filmdifferent from the High-k films 232A and 232B.

As described above, in the pixel 200 in FIG. 34 , the insulation layer230 has a structure in which the High-k films 232A and 232C (A+C) areformed in a part corresponding to the central area 221 that is thecentral portion between the right and left photoelectric conversiondevices 213A and 213B, which has a large fixed charge amount, and theHigh-k films 232A and 232B (A+B) are formed in a part corresponding tothe right-and-left area 222 excluding the central portion, which has alow fixed charge amount.

In other words, in at least one of the High-k film of the partcorresponding to the central area 221 and the High-k film of the partcorresponding to the right-and-left area 222, two or more different highdielectric constant films are stacked.

With such a structure, in the pixel 200 in FIG. 34 , in the case wherethere is a phase difference shift as indicated by the incident light ILin the figure, since the electrons photoelectrically converted in thevicinity of the silicon interface are accumulated in the desired rightand left photoelectric conversion devices 213A and 213B, it is possibleto improve the accuracy of phase difference detection.

Fifth Example of Structure

FIG. 35 is a cross-sectional view showing a fifth example of thestructure of the pixel in the tenth embodiment.

Similarly to FIG. 32 or the like described above, FIG. 35 shows, in anenlarged manner, an area including the central area 221 and theright-and-left area 222 on the silicon interface, of the cross sectionof the pixel 200 shown in FIG. 31 . However, the structure of the crosssection of the insulation layer 230 is different from that in theenlarged view of FIG. 32 or the like described above.

That is, the insulation layer 230 in FIG. 35 has a structure in whichthe layer to be formed between the oxide film 231 and the oxide film 233is obtained by stacking a first layer including only the High-k film232A, a second layer including the High-k film 232B and the High-k film232C, and a third layer partially including a High-k film 232D.

Here, the High-k film 232D is a high dielectric constant film differentfrom the High-k films 232A to 232C. Further, in the insulation layer230, a portion of the third layer excluding the High-k film 232D isformed to include a part of the oxide film 233 that is the upper layerthereof.

As described above, in the pixel 200 in FIG. 35 , the insulation layer230 has a structure in which the High-k films 232A, 232C, and 232D(A+C+D) are formed in a part corresponding to the central area 221 thatis the central portion between the right and left photoelectricconversion devices 213A and 213B, which has a large fixed charge amount,and the High-k films 232A and 232B (A+B) are formed in a partcorresponding to the right-and-left area 222 excluding the centralportion, which has a low fixed charge amount.

In other words, in at least one of the High-k film of the partcorresponding to the central area 221 and the High-k film of the partcorresponding to the right-and-left area 222, two or more different highdielectric constant films are stacked. Further, the number of stackedHigh-k films of the High-k film of the part corresponding to the centralarea 221 is larger than that of the High-k film of the partcorresponding to the right-and-left area 222.

With such a structure, in the pixel 200 in FIG. 35 , in the case wherethere is a phase difference shift as indicated by the incident light ILin the figure, since the electrons photoelectrically converted in thevicinity of the silicon interface are accumulated in the desired rightand left photoelectric conversion devices 213A and 213B, it is possibleto improve the accuracy of phase difference detection.

(Sixth Example of Structure)

FIG. 36 is a cross-sectional view showing a sixth example of thestructure of the pixel in the tenth embodiment.

Similarly to FIG. 32 or the like described above, FIG. 36 shows, in anenlarged manner, an area including the central area 221 and theright-and-left area 222 on the silicon interface, of the cross sectionof the pixel 200 shown in FIG. 31 . However, the structure of the crosssection of the insulation layer 230 is different from that in theenlarged view of FIG. 32 or the like described above.

That is, the insulation layer 230 in FIG. 36 has a structure in whichthe layer to be formed between the oxide film 231 and the oxide film 233is obtained by stacking the first layer including only the first layerincluding only the High-k film 232A, the second layer including theHigh-k film 232B and the High-k film 232C, and the third layer includingthe High-k film 232D and a High-k film 232E. Here, the High-k film 232Eis a high dielectric constant film different from the High-k films 232Ato 232D.

As described above, in the pixel 200 in FIG. 36 , the insulation layer230 has a structure in which the High-k films 232A, 232C, and 232D(A+C+D) are formed in a part corresponding to the central area 221 thatis the central portion between the right and left photoelectricconversion devices 213A and 213B, which has a large fixed charge amount,and the High-k films 232A, 232B, and 232E (A+B+E) are formed in a partcorresponding to the right-and-left area 222 excluding the centralportion, which has a low fixed charge amount.

In other words, in at least one of the High-k film of the partcorresponding to the central area 221 and the High-k film of the partcorresponding to the right-and-left area 222, two or more different highdielectric constant films are stacked. Further, it can be said that theHigh-k film of the part corresponding to the central area 221 and theHigh-k film of the part corresponding to the right-and-left area 222have the same number of stacked layers.

With such a structure, in the pixel 200 in FIG. 36 , in the case wherethere is a phase difference shift as indicated by the incident light ILin the figure, since the electrons photoelectrically converted in thevicinity of the silicon interface are accumulated in the desired rightand left photoelectric conversion devices 213A and 213B, it is possibleto improve the accuracy of phase difference detection.

(Seventh Example of Structure)

FIG. 37 is a cross-sectional view showing a seventh example of thestructure of the pixel in the tenth embodiment. Similarly to FIG. 32 orthe like described above, FIG. 37 shows, in an enlarged manner, an areaincluding the central area 221 and the right-and-left area 222 on thesilicon interface, of the cross section of the pixel 200 shown in FIG.31 . However, the structure of the cross section of the insulation layer230 is different from that in the enlarged view of FIG. 32 or the likedescribed above.

That is, the insulation layer 230 in FIG. 37 has a structure in whichthe layer to be formed between the oxide film 231 and the oxide film 233is obtained by stacking the first layer including only the High-k film232A and the second layer partially including the High-k film 232A.Further, in the insulation layer 230, a portion of the second layerexcluding the High-k film 232A is formed to include a part of the oxidefilm 233 that is the upper layer thereof.

As described above, in the pixel 200 in FIG. 37 , the insulation layer230 has a structure in which the High-k films 232A having differentheights are formed in a part corresponding to the central area 221 thatis the central portion between the right and left photoelectricconversion devices 213A and 213B, which has a large fixed charge amount,and a part corresponding to the right-and-left area 222 excluding thecentral portion, which has a low fixed charge amount.

In other words, in the insulation layer 230 in FIG. 37 , the High-k film232A has a convex structure because the part corresponding to thecentral area 221 of the central portion is higher than the partcorresponding to the right-and-left area 222 excluding the centralportion. Further, from such a structure, it can be also said that in theinsulation layer 230 in FIG. 37 , the thickness of the oxide film 233differs between the part corresponding to the central area 221 and thepart corresponding to the right-and-left area 222.

With such a structure, in the pixel 200 in FIG. 37 , in the case wherethere is a phase difference shift as indicated by the incident light ILin the figure, since the electrons photoelectrically converted in thevicinity of the silicon interface are accumulated in the desired rightand left photoelectric conversion devices 213A and 213B, it is possibleto improve the accuracy of phase difference detection.

(Eighth Example of Structure)

FIG. 38 is a cross-sectional view showing an eighth example of thestructure of the pixel in the tenth embodiment.

Similarly to FIG. 32 or the like described above, FIG. 38 shows, in anenlarged manner, an area including the central area 221 and theright-and-left area 222 on the silicon interface, of the cross sectionof the pixel 200 shown in FIG. 31 . However, the structure of the crosssection of the insulation layer 230 is different from that in theenlarged view of FIG. 32 or the like described above.

That is, the insulation layer 230 in FIG. 38 has a structure in whichthe layer to be formed between the oxide film 231 and the oxide film 233forms a layer including only the High-k film 232A, but a part of thelayer, which corresponds to the central area 221 of the central portion,protrudes downward with respect to the part corresponding to theright-and-left area 222 excluding the central portion.

As described above, in the pixel 200 in FIG. 38 , the insulation layer230 has a structure in which the thickness of the oxide film 231 differsbetween the part corresponding to the central area 221 that is thecentral portion between the right and left photoelectric conversiondevices 213A and 213B, which has a large fixed charge amount, and thepart corresponding to the right-and-left area 222 excluding the centralportion, which has a low fixed charge amount.

With such a structure, in the pixel 200 in FIG. 38 , in the case wherethere is a phase difference shift as indicated by the incident light ILin the figure, since the electrons photoelectrically converted in thevicinity of the silicon interface are accumulated in the desired rightand left photoelectric conversion devices 213A and 213B, it is possibleto improve the accuracy of phase difference detection.

(Ninth Example of Structure)

FIG. 39 is a cross-sectional view showing a ninth example of thestructure of the pixel in the tenth embodiment.

Although the case where the inter-pixel separation unit 215 includes anoxide film has been shown in FIG. 31 to FIG. 38 described above, thematerial of the inter-pixel separation unit 215 is not limited to theoxide film, and another material such as metal can be used. FIG. 39shows the structure in the case where instead of the inter-pixelseparation unit 215 described above, an inter-pixel separation unit 215Ais formed by embedding metal in the pixel 200.

Here, for example, the inter-pixel separation unit 215A is formed byembedding metal in the groove (trench) dug, in accordance with the shapeof the pixel in square units, into a square grid in a silicon layer inwhich a photoelectric conversion area has been formed from the side ofthe light incident surface using a DTI technology. Here, as the metal,tungsten (W), aluminum (Al), silver (Ag), rhodium (Rh), or the like canbe used.

For example, in the pixel 200 in A of FIG. 39 , in the case where thereis a phase difference shift as indicated by the incident light IL A inthe figure, since adjacent pixels in the silicon layer are physicallyseparated by the inter-pixel separation unit 215A, when the electronsphotoelectrically converted in the vicinity of the silicon interface areaccumulated in the desired right and left photoelectric conversiondevices 213A and 213B due to the potential gradient, the electrons canbe prevented from flowing into the adjacent pixels. Note that similarly,the electrons can be prevented from flowing into the adjacent pixelsalso in the case where there is no phase difference as shown in B ofFIG. 39 .

As described above, in the pixel 200 in FIG. 39 , it is possible tosuppress color mixing in the bulk and improve the separation ratio byinter-pixel separation between different colors by metal of the formedinter-pixel separation unit 215A. Note that an oxide film and metal havebeen described as the material of the inter-pixel separation unit 215(215A) in the above description, another substance may be used.

Note that although a groove is dug in the silicon layer 210 in which aphotoelectric conversion area has been formed from the side of the lightincident surface, and metal is embedded therein when forming theinter-pixel separation unit 215A in the pixel 200 in FIG. 39 , a pinningfilm (negative fixed charge film) and an insulation film can be providedon the side wall of the groove at that time. Here, as the pinning film,hafnium oxide (HfO₂), tantalum oxide (Ta₂O₅), or the like can be used.Further, as the insulation film, silicon dioxide (SiO₂) or the like canbe used.

(Tenth Example of Structure)

FIG. 40 is a cross-sectional view showing a tenth example of thestructure of the pixel in the tenth embodiment.

Although a structure in which the adjacent pixels are physicallyseparated by the inter-pixel separation unit 215 including an oxide filmor the inter-pixel separation unit 215A formed of metal has been shownin FIG. 31 to FIG. 38 or FIG. 39 described above, they may be separatedby impurities in the silicon layer.

The pixel 200 in FIG. 40 has a structure in which the adjacent pixelsare separated by the impurity distribution inside the silicon layerwithout forming a physical separation unit (inter-pixel separation unit)between the adjacent pixels. Here, A of FIG. 40 shows the case wherethere is a phase difference shift due to the incident light IL_(A), andB of FIG. 40 shows the case where there is no phase difference shift dueto the incident light IL_(B).

(Eleventh Example of Structure)

FIG. 41 is a cross-sectional view showing an eleventh example of thestructure of the pixel in the tenth embodiment.

Similarly to FIG. 31 described above, FIG. 41 shows the cross section ofthe pixel 200. However, this cross section is different from that crosssection in FIG. 31 described above in that a transparent electrode 241is formed in the central portion of the right and left photoelectricconversion devices 213A and 213B. Note that A of FIG. 41 shows the casewhere there is a phase difference shift due to the incident lightIL_(A), and B of FIG. 41 shows the case where there is no phasedifference shift due to the incident light IL_(B).

In the pixel 200 in FIG. 41 , the potential gradient from the centralportion between the right and left photoelectric conversion devices 213Aand 213B to the right and left photoelectric conversion devices 213A and213B can be formed by applying a negative bias to the transparentelectrode 241. As a result, in the pixel 200 in FIG. 41 , the electronsphotoelectrically converted in the vicinity of the silicon interface canbe accumulated in the desired right and left photoelectric conversiondevices 213A and 213B.

For example, in the pixel 200 in A of FIG. 41 , in the case where thereis a phase difference shift as indicated by the incident light IL_(A) inthe figure, by applying a negative bias to the transparent electrode 241to form the potential gradient, since the electrons photoelectricallyconverted in the vicinity of the silicon interface are accumulated inthe desired right and left photoelectric conversion devices 213A and213B, it is possible to improve the accuracy of phase differencedetection.

(Schematic Diagram of Potential Distribution)

FIG. 42 is a diagram schematically illustrating a potential distributionof the pixel in the tenth embodiment.

Note that in FIG. 42 , for comparison, the potential distribution of thepixel 200 to which the present technology is applied is shown in B ofFIG. 42 and the potential distribution of a general pixel 900 is shownin A of FIG. 42 . Here, the potential distribution is represented by thelines drawn on the right and left photoelectric conversion devices or onthe area between them. The denser these lines, the more potentialgradient there is.

As shown in the potential distribution of the pixel 900 in A of FIG. 42, generally, in the silicon layer, it is difficult to apply a potentialgradient on the light incident surface (e.g., back side) or the area ofthe central portion of the right and left photoelectric conversiondevices 913A and 913B.

Meanwhile, in the pixel 200, by changing the fixed charge amounts of thecentral area 221 and the right-and-left area 222 on the siliconinterface on the light incident surface (e.g., back side) to make iteasy to apply a potential gradient in the area of the light incidentsurface and the central portion, the potential gradient from the centralportion between the right and left photoelectric conversion devices 213Aand 213B to the right and left photoelectric conversion devices 213A and213B is formed.

Further, a transfer path P A shown in A of FIG. 42 and a transfer path PB shown in B of FIG. 42 respectively show the transfer paths derivedfrom the potential distributions of the pixel 900 and the pixel 200.Here, since there is an effect of potential and diffusion intransferring electrons, it is assumed that if the transfer takes time,the electrons are diffuses by that amount and the electrons cannot beaccumulated in the desired photoelectric conversion device 213 (213A or213B).

For example, in A of FIG. 42 , the transfer path P A is a combination ofa path directed downward and a path directed diagonally downward to theleft, and there is a possibility that the transfer of electrons takestime and the electrons are diffused. Meanwhile, for example, in B ofFIG. 42 , the transfer path P B is only a path directed diagonallydownward to the left, and electron transfer can be performed quickly.

That is, in the pixel 200 in B of FIG. 42 , since a potential gradientis applied by changing the fixed charge amounts of the central area 221and the right-and-left area 222 on the silicon interface on the lightincident surface, the transfer path P B is realized by, in a sense, theelectric field assist in the lateral direction (direction orthogonal tothe stacking direction) of the device boundary, and electron transfercan be performed more quickly. For that reason, in the pixel 200 in B ofFIG. 42 , the electrons photoelectrically converted in the vicinity ofthe silicon interface can be accumulated in the desired photoelectricconversion device 213 (213A or 213B).

The tenth embodiment has been described above.

(11) Eleventh Embodiment

As described above, in a solid-state imaging device such as a CMOS imagesensor, by employing a pixel structure in which a plurality ofphotoelectric conversion devices is formed immediately below a singleon-chip lens, since distance information can be acquired on the basis ofa signal for phase difference detection acquired from each pixel, it ispossible to simultaneously perform imaging and ranging. Further, in thepixel, a separation structure by impurity implantation can be usedbetween the right and left photoelectric conversion devices.

By employing such a structure, it is possible to simultaneously acquirea signal for imaging and a signal for detecting a phase difference.However, when photoelectrically converting light that has entered fromone on-chip lens, a component to be photoelectrically converted isgenerated in the part to be the separation wall located in the center ofthe right and left photoelectric conversion devices.

This separation wall has a certain width because this is formed byimplantation separation. For that reason, there is a possibility thatthe charges (electrons) photoelectrically converted in the area flowinto the photoelectric conversion device on the side opposite to thephotoelectric conversion device on the side assumed as the phasedifference, which generates an unnecessary component (color mixturecomponent). Due to this influence, the separation ratio becomesinsufficient, and the accuracy of phase difference detection is reduced.

Further, for example, in the case where the pixel has a separationstructure in which the separation wall located in the center of theright and left photoelectric conversion devices is formed by using a lowrefractive material instead of implantation separation, the light thathas entered the area is refracted and is likely to enter thephotoelectric conversion device of another adjacent pixel as the moreangled light, which makes optical color mixture of different colorsoccur.

In view of the above, in the eleventh embodiment, as pixels 300 to betwo-dimensionally arranged in the pixel array unit 11 of the CMOS imagesensor 10 (FIG. 1 ), a structure in which a low-refractive embeddingdevice separation area is formed in the central portion(inter-same-color central portion) of the photoelectric conversiondevices of the same colors and a metal embedding device separation areais formed in the central portion (inter-different-color central portion)of the photoelectric conversion devices of different colors is employed.By employing such a structure, it is possible to improve the separationratio and prevent color mixture from occurring.

Hereinafter, the structure of the pixel in the eleventh embodiment willbe described with reference to FIG. 43 to FIG. 48 .

First Example of Structure

FIG. 43 is a cross-sectional view showing a first example of thestructure of the pixel in the eleventh embodiment.

In FIG. 43 , the pixel 300 has a 2PD structure and includes an on-chiplens 311, a color filter 312, photoelectric conversion devices 313A and313B, an inter-pixel light blocking unit 314, and an inter-pixelseparation unit 315.

Note that since the on-chip lens 311 to the inter-pixel separation unit315 in the pixel 300 respectively correspond to the on-chip lens 111,the color filter 112, the photoelectric conversion devices 113A and113B, the inter-pixel light blocking unit 114, and the inter-pixelseparation unit 115 constituting the pixel 100 (FIG. 11 , etc.)according to the above-mentioned embodiments, description thereof willbe omitted as appropriate.

Further, for convenience of description, in the case where it isnecessary to particularly distinguish the colors of the pixels 300, theR pixel 300 will be expressed as “300 (R)” and the G pixel 300 will beexpressed as “300 (G)”.

In the pixel 300, the incident light IL condensed by the on-chip lens311 passes through the color filter 312 and is applied to thephotoelectric conversion area of the photoelectric conversion device313A or the photoelectric conversion device 313B.

Here, in the G pixel 300, a low-refractive material (embedding device)is embedded in an inter-same-color central portion 321 between thephotoelectric conversion device 313A and the photoelectric conversiondevice 313B on the side of the light incident surface to form a lowrefraction area 331 serving as a device separation area. As thelow-refractive material, for example, a low-refractive material such asan oxide film and glass can be used. More specifically, as thelow-refractive material, for example, a material having a refractiveindex lower than that of a silicon layer 310 (semiconductor layer) inwhich a photoelectric conversion area has been formed can be used.

The cross-sectional shape of the low refraction area 331 is a triangularshape that is tapered and increases in width as it approaches the lightincident surface. Further, the inter-same-color central portion 321,there is no low-refractive material (embedding device) serving as aseparation material at a predetermined bulk depth (e.g., approximatelyseveral 100 nm) from the light incident surface, and the lower area isseparated by impurities.

Further, in the case where the G pixel 300 and the R pixel 300 areadjacent to each other on the right and left, metal is embedded in agroove (trench) dug, in accordance with the shape of the pixel 300, inan inter-different-color central portion 322 between the photoelectricconversion device 313B on the right side of the G pixel 300 and thephotoelectric conversion device 313A on the left side of the R pixel 300from the side of the light incident surface to form the inter-pixelseparation unit 315. Here, as the metal, tungsten (W), aluminum (Al),silver (Ag), rhodium (Rh), or the like can be used.

As described above, since the pixel 300 in FIG. 43 has a structure inwhich the low refraction area 331 whose cross section has an invertedtriangle shape is formed in the inter-same-color central portion 321,the travelling direction of the light that has entered the lowrefraction area 331 is bent by the refracting surface. For example, inthe pixel 300, light that has entered from the diagonally upper rightdirection, of the light that has entered the low refraction area 331, isrefracted by a refracting surface 331A to enter the photoelectricconversion device 313A on the left side, while light that has enteredfrom the diagonally upper left is refracted by a refracting surface 331Bto enter the photoelectric conversion device 313B (arrows in thefigure).

For that reason, in the case where the condensing spot of the lightcondensed by the on-chip lens 311 enters the low refraction area 331formed in the inter-same-color central portion 321 between the right andleft photoelectric conversion devices 313A and 313B, the incident lighttravels to a certain depth as it is without being photoelectricallyconverted, enters the photoelectric conversion device 313A or thephotoelectric conversion device 313B when reaching the certain depth,and is photoelectrically converted. In particular, in the pixel 300 inFIG. 43 , it is possible to cause the light that has entered the centerof the light incident surface in the inter-same-color central portion321 to enter the right and left photoelectric conversion device 313A or313B.

Here, in the case where a separation wall is formed by implantationseparation in the inter-same-color central portion 321, there is apossibility that the electrons photoelectrically converted in the areato be the separation wall flow into the photoelectric conversion deviceon the side opposite to the photoelectric conversion device on the sideassumed as the phase difference, which reduces the accuracy of phasedifference detection, as described above.

Meanwhile, such an event can be avoided in the pixel 300 in FIG. 43 ,because the pixel 300 has a separation structure using the lowrefraction area 331 formed in the inter-same-color central portion 321and the incident light IL that has entered the low refraction area 331enters the right and left photoelectric conversion device 313A or 313Bas it is without being photoelectrically converted until reaching acertain depth. As a result, in the pixel 300 in FIG. 43 , it is possibleto optically and electrically improve the separation ratio, and improvethe accuracy of phase difference detection.

Meanwhile, in the case of employing the separation structure using thelow refraction area 331 in the inter-same-color central portion 321,there is a possibility that the light that has entered the lowrefraction area 331 is refracted to enter the photoelectric conversiondevice 313 of the adjacent pixel 300 of a different color as the moreangled light, as described above.

Meanwhile, in the pixel 300 in FIG. 43 , since the separation structureusing the low refraction area 331 in the inter-same-color centralportion 321 is provided and the inter-pixel separation unit 315 formedof metal is formed in the inter-different-color central portion 322, thelight that has been refracted by the low refraction area 331 formed inthe inter-same-color central portion 321 is reflected by the inter-pixelseparation unit 315. As a result, in the pixel 300 in FIG. 43 , it ispossible to prevent optical color mixture of different colors fromoccurring.

Note that in the pixel 300 in FIG. 43 , a groove (trench) is dug in thesilicon layer 310 in which a photoelectric conversion area has beenformed from the side of the light incident surface, and metal isembedded therein to form the inter-pixel separation unit 315. A pinningfilm (negative fixed charge film) and an insulation film can be providedon the side wall of the groove. Here, as the pinning film, hafnium oxide(HfO₂), tantalum oxide (Ta₂O₅), or the like can be used. Further, as theinsulation film, silicon dioxide (SiO₂) or the like can be used.

Second Example of Structure

FIG. 44 is a cross-sectional view showing a second example of thestructure of the pixel in the eleventh embodiment.

The shape of the cross section of the inter-same-color central portion321 of the pixel 300 in FIG. 44 is different from that of the pixel 300in FIG. 43 . That is, in the inter-same-color central portion 321 of thepixel 300 in FIG. 44 , the separation shape (shape of the cross section)of the low refraction area 331 having a tapered shape extends downwardwith a predetermined bulk depth (e.g., several 100 nm) from the lightincident surface and a certain width, and the shape of the lower areahas a rectangular shape (vertically long shape).

That is, the area below the low refraction area 331 is separated byimpurities without forming the low-refractive material as a separationmaterial in the case of the inter-same-color central portion 321 of thepixel 300 in FIG. 43 , while the low refraction area 331 extendsdownward with a certain width in the case of the inter-same-colorcentral portion 321 in the pixel 300 in FIG. 44 , so that the lowerportion having a rectangular shape (vertically long shape) separates thephotoelectric conversion device 313A and the photoelectric conversiondevice 313B.

As described above, in the pixel 300 in FIG. 44 , by forming, in asense, an inter-device separation unit of the triangle portion in thelow refraction area 331 and the portion extending downward therefrom,the photoelectric conversion device 313A and the photoelectricconversion device 313B are physically separated. As a result, in thepixel 300 in FIG. 44 , it is possible to improve the accuracy of phasedifference detection by preventing the output of one photoelectricconversion device 313 (313A or 313B) from mixing with the output of theother photoelectric conversion device 313 (313B or 313A).

Third Example of Structure

FIG. 45 is a cross-sectional view showing a third example of thestructure of the pixel in the eleventh embodiment.

The shape of the cross section of the inter-same-color central portion321 of the pixel 300 in FIG. 45 is different from that of the pixel 300in FIG. 43 . That is, in the inter-same-color central portion 321 of thepixel 300 in FIG. 45 , the separation shape (shape of the cross section)of the low refraction area 331 is a trapezoidal shape (trapezoid whosebottom is shorter than the top) tapered from the light incident surfaceto the surface (the side of the transistor device surface) oppositethereto.

As described above, in the pixel 300 in FIG. 45 , by forming, in asense, an inter-device separation unit of the trapezoidal portion in thelow refraction area 331, the photoelectric conversion device 313A andthe photoelectric conversion device 313B are physically separated. As aresult, in the pixel 300 in FIG. 45 , it is possible to improve theaccuracy of phase difference detection by preventing the output of onephotoelectric conversion device 313 from mixing with the output of theother photoelectric conversion device 313.

Fourth Example of Structure

FIG. 46 is a cross-sectional view showing a fourth example of thestructure of the pixel in the eleventh embodiment.

In the plan view shown in FIG. 46 , the X-X′ cross section correspondsto the cross-sectional view of the pixel 300 in FIG. 43 . That is, inthe pixel 300 in FIG. 46 , the inter-same-color central portion 321including the low refraction area 331 is formed between thephotoelectric conversion device 313A and the photoelectric conversiondevice 313B, and the shape thereof is a rectangular shape (verticallylong shape) when viewed from the side of the light incident surface.

Here, the dotted lines in the figure indicate the incident light IL. Inthe case where the light condensed by the on-chip lens 311 enters thelow refraction area 331, the incident light travels to a certain depthas it is without being photoelectrically converted, enters thephotoelectric conversion device 313A or the photoelectric conversiondevice 313B when reaching the certain depth, and is photoelectricallyconverted.

Note that although the case where the plan view shown in FIG. 46corresponds to the cross-sectional view of the pixel 300 in FIG. 43 hasbeen shown here, (the low refraction area 331 of) the inter-same-colorcentral portion 321 is formed between the photoelectric conversiondevice 313A and the photoelectric conversion device 313B similarly alsoin the pixel 300 in FIG. 44 or the pixel 300 in FIG. 45 .

Fifth Example of Structure

FIG. 47 is a cross-sectional view showing a fifth example of thestructure of the pixel in the eleventh embodiment.

In the plan view shown in FIG. 47 , the X-X′ cross section correspondsto the cross-sectional view of the pixel 300 in FIG. 43 . That is, inthe pixel 300 in FIG. 47 , the inter-same-color central portion 321including the low refraction area 331 is formed for four photoelectricconversion devices 313, i.e., the photoelectric conversion device 313A,the photoelectric conversion device 313B, a photoelectric conversiondevice 313C, and a photoelectric conversion device 313D, and the shapethereof is a rhombus shape when viewed from the side of the lightincident surface.

Here, the dotted line in the figure indicates the incident light IL. Inthe case where the light condensed by the on-chip lens 311 enters thelow refraction area 331, the incident light travels to a certain depthas it is without being photoelectrically converted, enters any of thephotoelectric conversion devices 313A to 313D when reaching the certaindepth, and is photoelectrically converted.

Note that although the case where the plan view shown in FIG. 47corresponds to the cross-sectional view of the pixel 300 in FIG. 43 hasbeen shown here, (the low refraction area 331 of) the inter-same-colorcentral portion 321 can be formed for four photoelectric conversiondevices 313 similarly also in the pixel 300 in FIG. 44 or the pixel 300in FIG. 45 .

Further, the separation layout by (the low refraction area 331 of) theinter-same-color central portion 321 shown in FIG. 46 and FIG. 47 isonly an example, and separation layout other than the rectangular shapefor the two photoelectric conversion devices 313 and the rhombus shapefor the four photoelectric conversion devices 313 may be used.

Sixth Example of Structure

FIG. 48 is a cross-sectional view showing a sixth example of thestructure of the pixel in the eleventh embodiment.

The shape of the cross section of the inter-different-color centralportion 322 of the pixel 300 in FIG. 48 is different from that of thepixel 300 in FIG. 44 . That is, in the inter-different-color centralportion 322 of the pixel 300 in FIG. 48 , a low refraction area 341formed of a low-refractive material is formed in the area (area in thedepth direction) below the inter-pixel separation unit 315 formed ofmetal.

More specifically, although a substance is embedded in a groove (trench)dug in silicon in which a photoelectric conversion area has been formedto form a separation unit for separating the pixels of different colors,a low-refractive material is embedded as a front side trench to form thelow refraction area 341 and metal is embedded as a back side trench toform the inter-pixel separation unit 315 in the pixel 300 in FIG. 48 .

Then, in the pixel 300 in FIG. 48 , with the structure combining theinter-pixel separation unit 315 and the low refraction area 341, theinter-different-color central portion 322 separates the pixels ofdifferent colors, e.g., the photoelectric conversion device 313B on theright side of the G pixel 300 and the photoelectric conversion device313A on the left side of the R pixel 300 shown in FIG. 48 .

The eleventh embodiment has been described above.

(12) Twelfth Embodiment

As described above, in a solid-state imaging device including a pixel inwhich a plurality of photoelectric conversion devices is formedimmediately below a single on-chip lens, it is possible to acquiredistance information on the basis of a signal for phase differencedetection acquired from each pixel.

However, in the structure of the general pixel, since a trade-offbetween the separation ratio and color mixture has occurred, it has beendifficult to improve the accuracy of phase difference detection whilesuppressing the color mixture. In order to eliminate such a trade-off,in the past, information regarding the phase difference has beenacquired simply by using only the bulk, or the separation ratio has beenincreased by using an optical waveguide without using an on-chip lensfor highly accurate detection. However, it has been demanded to furtherimprove the accuracy of phase difference detection while suppressing thecolor mixture.

In view of the above, in a twelfth embodiment, as pixels 400 to betwo-dimensionally arranged in the pixel array unit 11 of the CMOS imagesensor 10 (FIG. 1 ), a structure in which an on-chip lens is formed of aplurality of types of substances having different refractive indexes isemployed. By employing such as structure, it is possible to furtherimprove the accuracy of phase difference detection while suppressingcolor mixture. Here, the color mixture includes color mixture between aplurality of photoelectric conversion devices formed immediately below asingle on-chip lens.

Here, the structure of the pixel in the twelfth embodiment will bedescribed with reference to FIG. 49 to FIG. 56 .

First Example of Structure

FIG. 49 is a cross-sectional view showing a first example of a structureof a pixel in a twelfth embodiment.

In FIG. 49 , the pixel 400 has a 2PD structure, and includes an on-chiplens 411, a color filter 412, photoelectric conversion devices 413A and413B, an inter-pixel light blocking unit 414, and an inter-pixelseparation unit 415.

Note that since the on-chip lens 411 to the inter-pixel separation unit415 in the pixel 400 respectively correspond to the on-chip lens 111,the color filter 112, the photoelectric conversion devices 113A and113B, the inter-pixel light blocking unit 114, and the inter-pixelseparation unit 115 constituting the pixel 100 (FIG. 11 , etc.)according to the above-mentioned embodiments, description thereof willbe omitted here.

Further, for convenience of description, in the case where it isnecessary to particularly distinguish the colors of the pixel 400, the Rpixel 400 will be expressed as “400 (R)”, the G pixel 400 will beexpressed as “400 (G)”, and the B pixel 400 will be expressed as “400(B)”.

In the pixel 400, the on-chip lens 411 is formed of a member 411A and amember 411B as two types of substances having different refractiveindexes. In the on-chip lens 411, the member 411B has a shape dug into aV shape and a part of the member 411A (part on the side opposite to thelight incident surface) is embedded in the V-shape part.

That is, the member 411A (first member) has a curved surface on whichlight is incident and a part corresponding to the V-shape part of themember 411B, and the member 411B (second member) has a surface on theside opposite to the curved surface on which light is incident and apart having a V shape. Note that although the case where the junctionportion between the member 411A and the member 411B has a V shape willbe described, the shape of the junction portion may be another shapeother than the V shape.

For example, the member 411A is formed of a high-refractive material(High-n material), which is a material having a refractive index higherthan that of the member 411B. Meanwhile, for example, the member 411B isformed of a low-refractive material (Low-n material), which is amaterial having a refractive index lower than that of the member 411A.Further, an antireflection film 431 is formed on the surface on thelight incident side of the on-chip lens 411.

In the pixel 400, the incident light IL that has entered the on-chiplens 411 is refracted on the light incident surface of the member 411Aas indicated by the arrow of FIG. 49 , and then is refracted on theboundary between the member 411A and the member 411B to be applied tothe photoelectric conversion area of the photoelectric conversion device413A.

As described above, in the pixel 400 in FIG. 49 , the on-chip lens 411is formed of the member 411A and the member 411B having differentrefractive indexes, the light that has entered the photoelectricconversion device 413A or 413B is accumulated in the desired right andleft photoelectric conversion device 413A or 413B without being mixed(no color mixture).

FIG. 50 is a diagram showing an output result corresponding to anincident angle of light for each photoelectric conversion device 413 inthe pixel 400 in FIG. 49 .

Note that in FIG. 50 , for comparison, also the output result of rightand left photoelectric conversion devices 913A and 913B (existingstructure) of the general pixel 900 is shown together with the outputresult of the photoelectric conversion devices 413A and 413B (structureaccording to the present technology) of the pixel 400 in FIG. 49 .However, in the pixel 900, the structure of the on-chip lens 911 isdifferent from the structure of the on-chip lens 411 of the pixel 400.That is, in the pixel 900, the on-chip lens 911 is not formed of aplurality of substances having different refractive indexes.

That is, in FIG. 50 , for the pixel 400 in FIG. 49 , the output of thephotoelectric conversion device 413A on the left side is indicated by asolid curve A1, and the output of the photoelectric conversion device413B on the right side is indicated by a dotted curve B1. Further, forthe general pixel 900, the output of the photoelectric conversion device913A on the left side is indicated by a solid curve A2, and the outputof the photoelectric conversion device 913B on the right side isindicated by a dotted curve B2.

Here, in the curve A1 corresponding to the output of the photoelectricconversion device 413A on the left side and the curve B1 correspondingto the output of the photoelectric conversion device 413B on the rightside, the value of the output matches in the case where an incidentangle θi is 0 degree, i.e., light is incident from directly above. Thatis, the curve A1 and the curve B1 have a line-symmetric relationshipwith the output in the case where the incident angle θi=0 as thesymmetry axis.

Similarly, the curve A2 corresponding to the output of the photoelectricconversion device 913A on the left side and the curve B2 correspondingto the output of the photoelectric conversion device 913B on the rightside have a line-symmetric relationship with the output when theincident angle θi=0 as the symmetry axis.

At this time, when comparing the curves A1 and B1 of the pixel 400 inFIG. 49 and the curves A2 and B2 of the general pixel 900 with eachother, they have the following relationship.

That is, in the case where the incident angle Gi is negative andattention is paid to the curve A1 and the curve A2, although the peakvalues of the output of the photoelectric conversion device 413A and theoutput of the photoelectric conversion device 913A are substantially thesame, the output of the photoelectric conversion device 413B is mixedwith the output of the photoelectric conversion device 413A while theoutput of the photoelectric conversion device 913B is mixed with theoutput of the photoelectric conversion device 913A.

At this time, in the case where attention is paid to the curve B1 andthe curve B2, since the output of the photoelectric conversion device413B is small as compared with the output of the photoelectricconversion device 913B, the output of the photoelectric conversiondevice 413B mixed with the output of the photoelectric conversion device413A is reduced.

Meanwhile, in the case where the incident angle θi is positive andattention is paid to the curve B1 and the curve B2, although the peakvalues of the output of the photoelectric conversion device 413B and theoutput of the photoelectric conversion device 913B are substantially thesame, the output of the photoelectric conversion device 413A is mixedwith the output of the photoelectric conversion device 413B while theoutput of the photoelectric conversion device 913A is mixed with theoutput of the photoelectric conversion device 913B.

At this time, in the case where attention is paid to the curve A1 andthe curve A2, since the output of the photoelectric conversion device413A is small as compared with the output of the photoelectricconversion device 913A, the output of the photoelectric conversiondevice 413A mixed with the output of the photoelectric conversion device413B is reduced.

As describe above, in the pixel 400 in FIG. 49 , by forming the on-chiplens 411 of the member 411A and the member 411B having differentrefractive indexes, it is possible to improve the accuracy of phasedifference detection by preventing the output of one photoelectricconversion device 413 (413A or 413B) from mixing with the output of theother photoelectric conversion device 413 (413B or 413A). As a result,in the electronic apparatus including the CMOS image sensor 10 iscapable of realizing more-accurate autofocus.

Second Example of Structure

FIG. 51 is a cross-sectional view showing a second example of thestructure of the pixel in the twelfth embodiment.

The pixel 400 in FIG. 51 is different from the pixel 400 in FIG. 49 inthat an inter-device separation unit 416 is formed between the right andleft photoelectric conversion devices 413A and 413B, and the shape ofthe cross section of the on-chip lens 411 of the pixel 400 in FIG. 51 isdifferent from that in the pixel 400 in FIG. 49 . That is, in the pixel400 in FIG. 51 , the on-chip lens 411 further includes a member 411Cformed of a different substance in addition to two types of substances,i.e., the member 411A and the member 411B having different refractiveindexes.

In the on-chip lens 411, the member 411B has a shape dug into a V shapeon the side of the light incident surface, and a part (part on the sideopposite to the light incident surface) of the member 411A is embeddedin the V-shape part. Further, in the on-chip lens 411, the member 411Bhas a shape dug into a V shape also on the side opposite to the lightincident surface, and (all) the member 411C is embedded in the V-shapepart.

Although when forming the member 411A and the member 411C to have across section having a V shape for the member 411B, the vertexes of theV shapes are in contact with each other and the cross section having a Vshape of the member 411C is smaller than the cross section having a Vshape of the member 411A here, the shape of the cross section shown inFIG. 51 is merely an example and another shape may be employed.

Further, in the case where in the on-chip lens 411, the member 411A isformed of a high-refractive material (High-n material) and the member411B is formed of a low-refractive material (Low-n material), the member411C can be formed of a material having a refractive index capable ofreducing the amount of light to enter the inter-device separation unit416 formed in a silicon layer 410. In this case, the refractive index ofthe member 411C can be a refractive index different from those of themember 411A and the member 411B. Note that the refractive index of themember 411C may be the same refractive index as that of the member 411A.

As described above, in the pixel 400 in FIG. 51 , by employing astructure in which the on-chip lens 411 includes the member 411C inaddition to the member 411A and the member 411B in the case of providingthe inter-device separation unit 416 between the right and leftphotoelectric conversion devices 413A and 413B, it is possible to reducethe amount of light that enters the inter-device separation unit 416.

Third Example of Structure

FIG. 52 is a cross-sectional view showing a third example of thestructure of the pixel in the twelfth embodiment.

The pixel 400 in FIG. 52 is the same as the pixel 400 in FIG. 51 in thatthe inter-device separation unit 416 is provided and the on-chip lens411 includes the member 411A to the member 411C, but is different fromthe pixel 400 in FIG. 51 in that the height in the optical axisdirection (stacking direction) is optimized for each color in accordancewith the material of the on-chip lens 411.

In FIG. 52 , in each pixel 400, refractive indexes of the member 411A,the member 411B, and the member 411C are respectively indicated by n₁,n₂, and n₃. Further, in the G pixel 400, the curvature radius and heightof the on-chip lens 411 are respectively indicated by r_(G) and h_(G).Similarly, the curvature radius and height of the on-chip lens 411 inthe R pixel 400 are respectively indicated by r_(R) and h_(R), and thecurvature radius and height of the on-chip lens 411 in the B pixel 400are respectively indicated by r_(B) and h_(B).

Here, the height h G in the G pixel 400, the height h R in the R pixel400, and the height h B in the B pixel 400 are optimized for each colorin accordance with the material of the on-chip lens 411, i.e., therefractive indexes n₁, n₂, and n₃ of the member 411A to the member 411C.

For example, the relationship between the heights h_(G), h_(R), and h Bof the on-chip lens 411 for each color can be a relationship expressedby the following formula (1), taking into account of the chromaticaberration.

h_(R)>h_(G)>h_(B)  (1)

Note that although the case where the height h of the on-chip lens 411is adjusted as the parameter for performing optimization for each colorhas been exemplified here, another parameter may be used. For example,in the case of adjusting a curvature radius r of the on-chip lens 411,for example, a relationship expressed by the following formula (2) canbe used, taking into account of the chromatic aberration.

r_(R)>r_(G)>r_(R)  (2)

As described above, in the pixel 400 in FIG. 52 , by optimizing theparameter such as the height and the curvature radius for each color inaccordance with the material (refractive indexes of a plurality of typesof members) of the on-chip lens 411, for example, it is possible toimprove the quantum efficiency of each color and the separation ratio,or prevent color mixture from occurring.

Note that in FIG. 52 , in the G pixel 400, the angle between theboundary surface of the member 411B with the member 411A and thehorizontal plane is indicated by θ_(G).

Similarly, in the R pixel 400 and the B pixel 400, respectively, theangles between the boundary surface of the member 411B with the member411A and the horizontal plane are indicated by θ_(R) and θ_(B). Forexample, the angles θ_(G), θ_(R), and θ_(B) may be used as the parameterother than the above-mentioned height h and curvature radius r of theon-chip lens 411, and optimized.

Fourth Example of Structure

FIG. 53 is a cross-sectional view showing a fourth example of thestructure of the pixel in the twelfth embodiment.

The pixel 400 in FIG. 53 is different from the pixel 400 in FIG. 49 inthat the inter-device separation unit 416 is provided and a controlmember 421 is provided between the member 411A and the member 411B inthe on-chip lens 411.

The control member 421 is formed of, for example, a photonic crystal.The photonic crystal is a nanostructure whose refractive index changesperiodically. By forming the control member 421 between the member 411Aand the member 411B, the on-chip lens 411 has a structure capable ofcontrolling the dependency on the incident angle of light.

That is, by providing the control member 421 formed of a photoniccrystal, for example, the pixel 400 can have a structure that totallyreflects the incident light from the direction on the left side in thefigure so as not to enter the photoelectric conversion device 413A onthe left side, or a structure totally reflects the incident light fromthe direction on the right side in the figure so as not to enter thephotoelectric conversion device 413B on the right side. That is, thepixel 400 has a structure in which the dependency on the incident angleis further increased by efficiently using the dependency on the incidentangle of the photonic crystal.

As described above, in the pixel 400 in FIG. 53 , by employing astructure in which the dependency on the incident angle of light can becontrolled by forming the control member 421 formed of a photoniccrystal between the member 411A and the member 411B in the on-chip lens411, it is possible to further improve the accuracy of phase differencedetection while suppressing color mixture.

Fifth Example of Structure

FIG. 54 is a cross-sectional view showing a fifth example of thestructure of the pixel in the twelfth embodiment.

The pixel 400 in FIG. 54 is different from the pixel 400 in FIG. 53 inthat the color filters 412 corresponding to the respective colors areremoved and the control member 421 (421R, 421G, and 421B) has a spectralfunction.

The control member 421 (421R, 421G, and 421B) is formed of, for example,a photonic crystal. Here, since in the photonic crystal, only lighthaving a specific wavelength resonates with the periodic structure tocause reflection and transmission, a spectral function can be providedusing this characteristic similarly to the color filter.

That is, the G pixel 400 in FIG. 54 has a structure in which the G colorfilter 412 is not provided, by making it possible to cause, when formingthe control member 421G formed of a photonic crystal between the member411A and the member 411B, the control member 421G to function as afilter through which the green (G) wavelength component is transmittedby the photonic crystal structure.

Similarly, the R pixel 400 in FIG. 54 has a structure in which the Rcolor filter 412 is not provided, by causing, when forming the controlmember 421R, the control member 421R to function as a filter throughwhich the red (R) wavelength component is transmitted by the photoniccrystal structure. Further, similarly, the B pixel in FIG. 54 has astructure in which the B color filter 412 is not provided, by causing itto function as a filter through which the blue (B) component istransmitted by the photonic crystal structure.

As described above, the pixel 400 in FIG. 54 can have a structure inwhich not only the dependency on the incident angle can be furtherincreased by efficiently using the dependency on the incident angle ofthe photonic crystal but also the color filter 412 is not provided, bycausing, when forming the control member 421 formed of a photoniccrystal, the control member 421 to function similarly as the colorfilter for each color using the photonic crystal structure.

Sixth Example of Structure

FIG. 55 is a cross-sectional view showing a sixth example of thestructure of the pixel in the twelfth embodiment.

Although the pixels 400 are two-dimensionally (in a matrix) arranged inthe pixel array unit 11 (FIG. 1 ), it goes without saying that, of thepixels to be arranged in the pixel array unit 11 (FIG. 1 ), all thepixel may have a structure similar to that of the pixel 400 or a part ofthe pixels may have a structure similar to that of the pixel 400.

For example, as shown in FIG. 55 , also in the case where the pixelarray unit 11 employs the arrangement pattern in which shared pixelseach sharing the pixel circuit by neighboring pixels (2×2, i.e., fourpixels of the same color) of the same color are regularly arranged, apart of the pixels can have a structure similar to that of the pixel400.

However, in the pixel arrangement shown in FIG. 55 , each pixel 400 hasa structure (1PD structure) including one photoelectric conversiondevice. Here, in order to distinguish from the above-mentioned pixel 400having the 2PD structure, the pixel 400 having the 1PD structure will bereferred to as the pixel 400 (1PD).

Here, for example, in the pixel arrangement shown in FIG. 55 , anelliptical on-chip lens 411E is formed for a G pixel 400-11 (1PD) and aG pixel 400-12 (1PD) arranged in the same row. This on-chip lens 411Ehas a structure formed of a plurality of types of substances havingdifferent refractive indexes similarly to the above-mentioned on-chiplens 411 (FIG. 49 , etc.).

That is, a structure in which one photoelectric conversion device 413(corresponding to, for example, the photoelectric conversion device 413Ain FIG. 49 ) of the G pixel 400-11 (1PD) and one photoelectricconversion device 413 (corresponding to, for example, the photoelectricconversion device 413B in FIG. 49 ) of the G pixel 400-12 (1PD) areprovided for the one on-chip lens 411E is provided. Then, here, phasedifference detection is performed using the output of each of thephotoelectric conversion device 413 of the G pixel 400-11 (1PD) and thephotoelectric conversion device 413 of the G pixel 400-12 (1PD) arrangedin the same row.

Further, similarly, the elliptical on-chip lens 411E is formed also fora G pixel 400-21 (1PD) and a G pixel 400-22 (1PD) arranged on the samerow, or the like, and phase difference detection using the output ofeach of the photoelectric conversion devices 413 (corresponding to, forexample, the photoelectric conversion devices 413A and 413B in FIG. 49 )of the G pixels 400 (1PD) is performed.

Further, for example, the elliptical on-chip lens 411E may be formed inthe column direction as in a G pixel 400-33 (1PD) and a G pixel 400-43(1PD) or a G pixel 400-34 (1PD) and a G pixel 400-44 (1PD) arranged inthe same column.

Note that although the case where two G pixels 400 (1PD) are arrangedfor the elliptical on-chip lens 411E has been described in the pixelarrangement shown in FIG. 55 , R pixels 400 (1PD) or B pixels 400 (1PD)may be arranged for the elliptical on-chip lens 411E in the rowdirection or column direction.

Seventh Example of Structure

FIG. 56 is a cross-sectional view showing a seventh example of thestructure of the pixel in the twelfth embodiment.

As shown in FIG. 56 , also in the case where a Bayer array is employedin the pixel array unit 11 (FIG. 1 ), a part of the pixels can have astructure similar to that of the pixel 400. However, also in the pixelarrangement shown in FIG. 56 , each pixel 400 has a structure (1PDstructure) including one photoelectric conversion device, and the pixel400 having the 1PD structure will be referred to as the pixel 400 (1PD).

Here, for example, in the pixel arrangement shown in FIG. 56 , theelliptical on-chip lens 411E is formed for the G pixel 400-22 (1PD) anda G pixel 400-32 (1PD) arranged in the same row. This on-chip lens 411Ehas a structure formed of a plurality of types of substances havingdifferent refractive indexes, similarly to the above-mentioned on-chiplens 411 (FIG. 49 , etc.).

That is, a structure in which one photoelectric conversion device 413(corresponding to, for example, the photoelectric conversion device 413Ain FIG. 49 ) of the G pixel 400-22 (1PD) and one photoelectricconversion device 413 (corresponding to, for example, the photoelectricconversion device 413B in FIG. 49 ) of the G pixel 400-32 (1PD) areprovided for one on-chip lens 411E is provided, and phase differencedetection using the output of each of the photoelectric conversiondevices 413 of the G pixels 400 (1PD) is performed.

Further, similarly, the elliptical on-chip lens 411E is formed also fora G pixel 400-27 (1PD) and a G pixel 400-37 (1PD) arranged in the samecolumn, or the like, and phase difference detection using the output ofeach of the photoelectric conversion devices 413 (corresponding to, forexample, the photoelectric conversion devices 413A and 413B in FIG. 49 )of the G pixels 400 is performed.

Further, for example, the elliptical on-chip lens 411E in the rowdirection may be formed as in a G pixel 400-71 (1PD) and a G pixel400-72 (1PD) or a G pixel 400-66 (1PD) and a G pixel 400-67 (1PD)arranged in the same row, or the like.

Note that although the case where two G pixels 400 (1PD) are arrangedfor the elliptical on-chip lens 411E has been described in the Bayerarrangement shown in FIG. 56 , R pixels 400 (1PD) or B pixels 400 (1PD)may be arranged for the elliptical on-chip lens 411E in the rowdirection or the column direction.

The twelfth embodiment has been described above.

(13) Thirteenth Embodiment

FIG. 57 shows the structure of the pixels to be two-dimensionallyarranged in the pixel array unit of the CMOS image sensor.

In FIG. 57 , the pixel 900 has a 2PD structure including thephotoelectric conversion device 913A and the photoelectric conversiondevice 913B. In the photoelectric conversion devices 913A and 913B,charges corresponding to the components of the respective colors aregenerated from the light that has been condensed by the on-chip lens 911and transmitted through the color filter through which the wavelength ofeach of the colors, i.e., red (R), green (G), and blue (B).

In the pixel 900, the charges generated by the photoelectric conversiondevice 913A and the photoelectric conversion device 913B are read via atransfer gate and used as information for phase difference detection.

Incidentally, in the pixel 900, as a structure for preventing the outputof one photoelectric conversion device 913 mixing with the output of theother photoelectric conversion device 913, a structure in which aphysical separation unit is formed between the right and leftphotoelectric conversion devices 913 can be employed.

FIG. 58 shows the structure of the pixel in which a physical separationunit is provided between the right and left photoelectric conversiondevices.

In the pixel 900 in FIG. 58 , an inter-device separation unit 916 isformed between the photoelectric conversion device 913A and thephotoelectric conversion device 913B, and the photoelectric conversiondevice 913A and the photoelectric conversion device 913B are physicallyseparated. By forming the inter-device separation unit 916 in this way,it is possible to improve the accuracy of phase difference detection bypreventing the output of one photoelectric conversion device 913 frommixing with the output of the other photoelectric conversion device 913.

However, in the pixel 900, in the case where the inter-device separationunit 916 is formed between the photoelectric conversion device 913A andthe photoelectric conversion device 913B from the side of the lightincident surface (back side) using a DTI technology in order to improvethe characteristics of phase difference, since the condensing spot islocated immediately above the processing surface, there is a possibilitythat scattering (arrows SL in FIG. 58 ) of light from the processinginterface occurs, which deteriorates spectral characteristics anddegrades a picked-up image.

In view of the above, in the thirteenth embodiment, as pixels 500 to betwo-dimensionally arranged in the pixel array unit 11 of the CMOS imagesensor 10 (FIG. 1 ), a structure in which a vertical transistor has beenformed in the central portion (inter-same-color central portion) of thephotoelectric conversion devices of the same color is employed. Byemploying such a structure, it is possible to optically separateincident light to enter the desired right and left photoelectricconversion devices more efficiently.

Hereinafter, the structure of the pixel in the thirteenth embodimentwill be described with reference to FIG. 59 to FIG. 61 .

First Example of Structure

FIG. 59 is a cross-sectional view showing a first example of a structureof the pixel in the thirteenth embodiment.

In FIG. 59 , the pixel 500 has a 2PD structure, and includes an on-chiplens 511, a color filter 512, photoelectric conversion devices 513A and513B, an inter-pixel light blocking unit 514, and an inter-pixelseparation unit 515.

Note that in the pixel 500, since the on-chip lens 511 to theinter-pixel separation unit 515 respectively correspond to the on-chiplens 111, the color filter 112, the photoelectric conversion devices113A and 113B, the inter-pixel light blocking unit 114, and theinter-pixel separation unit 115 constituting the pixel 100 (FIG. 11 ,etc.) in the above-mentioned embodiments, description thereof will beomitted here as appropriate.

In the pixel 500, the incident light IL condensed by the on-chip lens511 is transmitted through the color filter 512 and applied to thephotoelectric conversion area in the photoelectric conversion device513A or the photoelectric conversion device 513B.

Here, in an inter-same-color central portion 521 between thephotoelectric conversion device 513A and the photoelectric conversiondevice 513B in the pixel 500, a vertical transistor 531 is formed in asilicon layer 510 from a surface on the side opposite to the lightincident surface. That is, here, in addition to the transfer transistorsprovided for the photoelectric conversion devices 513A and 513B, thevertical transistor 531 is provided between the devices.

Instead of forming, in the inter-same-color central portion 521, aninter-device separation unit from the light incident surface (e.g., backside), the vertical transistor 531 is formed from the surface (e.g.,front side) on the side opposite thereto as described above, and thus,it is possible to realize efficient optical separation for the right andleft photoelectric conversion devices 513A and 513B without condensinglight immediately above the processing surface.

Further, here, the function of the vertical transistor 531 formed in theinter-same-color central portion 521 may be used. That is, by applying avoltage (e.g., a positive voltage) to the vertical transistor 531, it ispossible to form a blooming path (channel) between the photoelectricconversion device 513A and the photoelectric conversion device 513B(above the vertical transistor 531). In the pixel 500, via this bloomingpath, it is possible to exchange the charges accumulated in the rightand left photoelectric conversion devices 513A and 513B.

Here, since the pixel 500 can be used as both a pixel for acquiring animage and a pixel for detecting a phase difference, the pixel 500functions as a pixel for detecting a phase difference at the time ofautofocusing and is capable of functioning a pixel for acquiring animage at the time of imaging after the end of the autofocusing.

Then, in the case where the pixel 500 functions as a pixel for acquiringan image, for example, when the charges accumulated in one photoelectricconversion device 513 (513A or 513B) of the right and left photoelectricconversion devices 513A and 513B are likely to be saturated (the chargesgenerated by the right and left photoelectric conversion devices 513Aand 513B are unbalanced), it is possible to prevent the charges frombeing saturated, by accumulating the charges in the other photoelectricconversion device 513 (513B or 513A) via the blooming path. As a result,in the pixel 500, it is possible to control the output linearity byperforming control of the voltage on the vertical transistor 531.

Note that in the pixel 500, in an inter-different-color central portion522 between the photoelectric conversion device 513A or 513B and aphotoelectric conversion device of an adjacent pixel, the inter-pixelseparation unit 515 formed of metal or the like is formed in the siliconlayer 510 from the light incident surface. Here, as the metal, tungsten(W), aluminum (Al), silver (Ag), rhodium (Rh), or the like can be used.

Further, in the pixel 500 in FIG. 59 , although a groove is dug in thesilicon layer 510 in which a photoelectric conversion area has beenformed from the side of the light incident surface, and metal isembedded therein when forming the inter-pixel separation unit 515, apinning film (negative fixed charge film) and an insulation film can beprovided on the side wall of the groove at that time. Here, as thepinning film, hafnium oxide (HfO₂), tantalum oxide (Ta₂O₅), or the likecan be used. Further, as the insulation film, silicon dioxide (SiO₂) orthe like can be used. As described above, the pixel 500 in FIG. 59 has astructure in which the vertical transistor 531 is formed in theinter-same-color central portion 521 between the photoelectricconversion device 513A and the photoelectric conversion device 513B fromthe surface on the side opposite to the light incident surface, andthus, a groove (trench) can be formed without exposing the processingsurface to the light reception surface side of the photoelectricconversion devices 513A and 513B, thereby achieving high phasedifference separation characteristics.

Second Example of Structure

FIG. 60 is a cross-sectional view showing a second example of thestructure of the pixel in the thirteenth embodiment.

The pixel 500 in FIG. 60 is different from the pixel 500 in FIG. 59 inthat a vertical transistor 532 is formed instead of the inter-pixelseparation unit 515 in the inter-different-color central portion 522.

That is, the pixel 500 in FIG. 60 has a structure in which the verticaltransistor 531 is formed in the inter-same-color central portion 521from the surface on the side opposite to the light incident surface andalso the vertical transistor 532 is formed in the inter-different-colorcentral portion 522 from the surface on the side opposite to the lightincident surface.

In the inter-different-color central portion 522, instead of forming aninter-pixel separation unit from the light incident surface, thevertical transistor 532 is formed from the surface on the side oppositethereto, and thus, the effect of suppressing color mixture due to longwavelength light can be maintained although it is inferior to thestructure in which an inter-pixel separation unit is formed.

Further, here, the function of the vertical transistor 532 formed in theinter-different-color central portion 522 may be used. That is, byapplying a voltage (e.g., a negative voltage) to the vertical transistor532, charges (negative charges) can be generated in the silicon layer510 to enhance pinning. As a result, white spots can be suppressed.Further, also in this case, by applying a voltage (e.g., a positivevoltage) to the vertical transistor 531 formed in the inter-same-colorcentral portion 521, it is possible to control the output linearity ofthe right and left photoelectric conversion devices 513A and 513B.

As described above, since the pixel 500 FIG. 60 has a structure in whichthe vertical transistor 531 and the vertical transistor 532 arerespectively formed in the inter-same-color central portion 521 and theinter-different-color central portion 522 from the surface on the sideopposite to the light incident surface, it is possible to achieve highphase difference separation characteristics, enhance pinning, andcontrol the output linearity while maintaining the effect of suppressingcolor mixture due to long wavelength light.

Third Example of Structure

FIG. 61 is a cross-sectional view showing a third example of thestructure of the pixel in the thirteenth embodiment.

The pixel 500 in FIG. 61 is different from the pixel 500 in FIG. 59 inthat the vertical transistor 532 is formed not only in theinter-same-color central portion 521 but also in theinter-different-color central portion 522.

That is, the pixel 500 in FIG. 61 has a structure in which theinter-pixel separation unit 515 formed of metal or the like is formed inthe inter-different-color central portion 522 from the light incidentsurface and the vertical transistor 532 is formed from the surface onthe side opposite thereto.

By employing such a structure, it is possible to increase the effect ofsuppressing color mixture by the amount of further forming the verticaltransistor 532, as compared with the case where only the inter-pixelseparation unit 541 is formed in the inter-different-color centralportion 522.

Further, also in this case, by applying a voltage (e.g., a negativevoltage) to the vertical transistor 532 using the function of thevertical transistor 532 formed in the inter-different-color centralportion 522, it is possible to enhance pinning and suppress white spots.Note that by applying a voltage (e.g., a positive voltage) to thevertical transistor 531 formed in the inter-same-color central portion521, it is possible to control the output linearity of the right andleft photoelectric conversion devices 513A and 513B.

As described above, since the pixel 500 in FIG. 61 has a structure inwhich the inter-pixel separation unit 515 is formed in theinter-different-color central portion 522 from the light incidentsurface and the vertical transistor 531 and the vertical transistor 532are respectively formed in the inter-same-color central portion 521 andthe inter-different-color central portion 522 from the surface on theside opposite to the light incident surface, it is possible to achievehigh phase difference separation characteristics, further increase theeffect of suppressing color mixture, enhance pinning, and control theoutput linearity.

The thirteenth embodiment has been described above.

4. Circuit Configuration of Pixel

FIG. 62 is a diagram showing a circuit configuration of the pixel 100 ineach embodiment.

In FIG. 62 , the respective two pixels 100 provided at the upper stageand the lower stage in FIG. 62 share a floating diffusion area (FD:Floating Diffusion). Note that each of the pixels 100 has the 2PDstructure including the photoelectric conversion device 113A and thephotoelectric conversion device 113B, and one on-chip lens 111 and onecolor filter 112 are shared. Further, transfer transistors 151A and 151Brespectively correspond to the transfer gates 151A and 151B.

An anode of the photodiode as the photoelectric conversion device 113Ais grounded, and a cathode of the photodiode is connected to a source ofthe transfer transistor 151A. A drain of the transfer transistor 151A isconnected to a source of a reset transistor 152 and a gate of anamplification transistor 153.

An anode of the photodiode as the photoelectric conversion device 113Bis grounded, and a cathode of the photodiode is connected to a source ofthe transfer transistor 151B. A drain of the transfer transistor 151B isconnected to the source of the reset transistor 152 and the gate of theamplification transistor 153.

The connection point between the drains of the transfer transistors 151Aand 151B of the two pixels at the upper stage, the source of the resettransistor 152, and the gate of the amplification transistor 153 forms afloating diffusion area (FD) 161. Similarly, the connection pointbetween the drains of the transfer transistors 151A and 151B of the twopixels at the lower stage, the source of the reset transistor 152, andthe gate of the amplification transistor 153 forms a floating diffusionarea (FD) 161.

A drain of the reset transistor 152 and a source of the amplificationtransistor 153 are connected to a power source. A drain of theamplification transistor 153 is connected to a source of a selectiontransistor 154, and a drain of the selection transistor 154 is connectedto the vertical signal line 22.

Gates of the transfer transistors 151A and 151B, a gate of the resettransistor 152, and a gate of the selection transistor 154 are connectedto the vertical drive circuit 12 (FIG. 1 ) via the pixel drive line 21,and a pulse as a drive signal is supplied to each gate of thetransistors.

Next, the basic function of the pixel 100 shown in FIG. 62 will bedescribed.

The reset transistor 152 turns on/off discharging of charges accumulatedin the floating diffusion area (FD) 161 in accordance with a drivesignal RST input to the gate of the reset transistor 152.

The photoelectric conversion device 113A performs photoelectricconversion on incident light, generates charges corresponding to theamount of the incident light, and accumulates the charges. The transfertransistor 151A turns on/off transferring of the charges from thephotoelectric conversion device 113A to the floating diffusion area (FD)161 in accordance with a drive signal TRG input to the gate of thetransfer transistor 151A.

The photoelectric conversion device 113B performs photoelectricconversion on incident light, generates charges corresponding to theamount of the incident light, and accumulates the charges. The transfertransistor 151B turns on/off transferring of the charges from thephotoelectric conversion device 113B to the floating diffusion area (FD)161 in accordance with a drive signal TRG input to the gate of thetransfer transistor 151B.

The floating diffusion area (FD) 161 has a function of accumulating thecharges transferred from the photoelectric conversion device 113A viathe transfer transistor 151A or the charges transferred from thephotoelectric conversion device 113B via the transfer transistor 151B.The potential of the floating diffusion area (FD) 161 is modulateddepending on the amount of the accumulated charges.

The amplification transistor 153 operates as an amplifier that regardsthe change in the potential of the floating diffusion area (FD) 161connected to the gate of the amplification transistor 153 as an inputsignal, and the output signal voltage is output to the vertical signalline 22 via the selection transistor 154.

The selection transistor 154 turns on/off outputting of a voltage signalfrom the amplification transistor 153 to the vertical signal line 22 inaccordance with a drive signal SEL input to the gate of the selectiontransistor 154.

As described above, the pixel 100 having the 2PD structure is driven inaccordance with the drive signals (TRG, RST, and SEL) supplied from thevertical drive circuit 12 (FIG. 1 ).

Note that although the circuit configuration of the pixel 100 in thefirst embodiment to the ninth embodiment has been described in FIG. 62 ,a circuit configuration similar thereto can be employed also for thepixel 200 in the tenth embodiment, the pixel 300 in the eleventhembodiment, the pixel 400 in the twelfth embodiment, or the pixel 500 inthe thirteenth embodiment.

5. Modified Example Example of Combination of Embodiments

It goes without saying that the above-mentioned nine embodiments areeach established as a single embodiment. An embodiment in which all or apart of the embodiments are combined in a possible range may beemployed.

For example, by combining the above-mentioned second embodiment and theabove-mentioned seventh embodiment, the projection portion 114P may beformed by the inter-pixel light blocking unit 114 in the plurality ofpixels 100 (pixels 100 having the 1PD structure) in a configuration inwhich the plurality of pixels 100 are arranged in the row direction orthe column direction with respect to the on-chip lens 111E having anelliptical shape in the row direction or the column direction.

Further, for example, by combining the above-mentioned third embodimentand the above-mentioned seventh embodiment, the projection portion 114Pmay be formed by the inter-pixel light blocking unit 114 as well as theprojection portion 115P may be formed by the inter-pixel separation unit115 in the plurality of pixels 100 (pixels 100 having the 1PD structure)in a configuration in which the plurality of pixels 100 are arranged inthe row direction or the column direction with respect to the on-chiplens 111E having an elliptical shape in the row direction or the columndirection.

For example, by combining the above-mentioned second embodiment and theabove-mentioned eighth embodiment, the projection portion 114P may beformed by the inter-pixel light blocking unit 114 in the pixels 100(pixels 100 having the 1PD structure) in two rows and two columns in aconfiguration in which the pixels 100 in two rows and two columns arearranged with respect to one on-chip lens 111.

Further, for example, by combining the above-mentioned third embodimentand the above-mentioned eighth embodiment, the projection portion 114Pmay be formed by the inter-pixel light blocking unit 114 as well as theprojection portion 115P may be formed by the inter-pixel separation unit115 in the pixels 100 (pixels 100 having the 1PD structure) in two rowsand two columns in a configuration in which the pixels 100 in two rowsand two columns are arranged with respect to one on-chip lens 111.

Further, for example, by combining any of the above-mentioned first toninth embodiments and any of the above-mentioned tenth to thirteenthembodiments, for example, the inter-pixel separation unit 215 (theinter-pixel separation unit 315, the inter-pixel separation unit 415, orthe inter-pixel separation unit 515) may form a projection portion 215P(a projection portion 315P, a projection portion 415P, or a projectionportion 515P) in the pixel 200 (the pixel 300, the pixel 400, or thepixel 500).

In this case, for example, the inter-pixel light blocking unit 214 (theinter-pixel light blocking unit 314, the inter-pixel light blocking unit414, or the inter-pixel light blocking unit 514) may form a projectionportion 214P (a projection portion 314P, a projection portion 414P, or aprojection portion 514P) in the pixel 200 (the pixel 300, the pixel 400,or the pixel 500).

Note that although the pixel 100 has a structure (2PD structure) inwhich the right and left photoelectric conversion devices 113A and 113Bare provided for one on-chip lens 111 in the above description, theright and left photoelectric conversion devices 113A and 113B may beregarded as the left pixel 100A and the right pixel 100B. That is, itcan be said that the pixel 100 is a pixel unit that includes a leftpixel 100A including a photoelectric conversion device 113A and a rightpixel 100B including a photoelectric conversion device 113B.

Similarly, also the pixel 200 (the pixels 300, the pixel 400, or thepixel 500) can be regarded as the pixel unit that includes a left pixel200A (a left pixel 300A, a left pixel 400A, or a left pixel 500 A)including the photoelectric conversion device 213A (the photoelectricconversion device 313A, the photoelectric conversion device 413A, or thephotoelectric conversion device 513A) and a right pixel 200B (a rightpixel 300B, a right pixel 400B, or a right pixel 500B) including thephotoelectric conversion device 213B (the photoelectric conversiondevice 313B, the photoelectric conversion device 413B, or thephotoelectric conversion device 513B).

Note that although the case where a photodiode (PD) is used as thephotoelectric conversion devices 113A and 113B of the pixel 100 has beendescribed above, for example, another member (device) such as aphotoelectric conversion film may be used. Further, it can be said thatthe on-chip lens 111 is a lens on the pixel, which perform focusdetection, and is also a microlens. The same applies also to the pixel200, the pixel 300, the pixel 400, or the pixel 500.

Further, although the inter-pixel light blocking unit 114 and theinter-pixel separation unit 115 are formed in a square grid for thepixel 100 in the above description, the present technology is notlimited to the square grid and another shape such as a quadrilateralincluding a rectangle may be used. Further, also the pixel 100 is notlimited to a square unit, and may be formed in another unit. The sameapplies also to the pixel 200, the pixel 300, the pixel 400, or thepixel 500.

Further, although R pixels, G pixels, and B pixels have been shown asthe pixels 100 (the pixels 200, the pixels 300, the pixels 400, or thepixels 500) to be two-dimensionally arranged in the pixel array unit 11(FIG. 1 ) in the above description, for example, pixels other than RGBpixels, such as W pixels corresponding to white (W) and IR pixelscorresponding to infrared light (IR) may be included. Note that the Wpixel is a pixel that causes light in the entire wavelength region to betransmitted therethrough and obtains charges corresponding to the light.Further, the IR pixel is a pixel that causes infrared light (IR) to betransmitted therethrough and has sensitivity to the wavelength band ofinfrared light.

(Another Example of Solid-State Imaging Device)

Further, although a case where an embodiment of the present technologyis applied to the CMOS image sensor in which the pixels aretwo-dimensionally arranged has been described as an example in theabove-mentioned embodiments, the present technology is not limited toapplication to the CMOS image sensor. That is, the present technology isapplicable to all X-Y address type solid-state imaging devices in whichthe pixels are two-dimensionally arranged, e.g., a CCD (Charge CoupledDevice) image sensor.

Further, the present technology is not limited to application to asolid-state imaging device that detects distribution of the amount ofincident light of visible light and images the distribution as an image,and is applicable to all solid-state imaging devices that imagedistribution of the incident amount of infrared rays, X-rays, particles,or the like, as an image. Further, although the pixel 100 having the 2PDstructure in which two photoelectric conversion devices 113 are formedwith respect to one on-chip lens 111 has been mainly described in theabove-mentioned embodiments, the present technology is applicable to thepixel 100 in which a plurality of photoelectric conversion devices 113are formed with respect to one on-chip lens 111, similarly.

6. Configuration of Electronic Apparatus

FIG. 63 is a block diagram showing a configuration example an electronicapparatus including a solid-state imaging device to which an embodimentof the present technology is applied.

An electronic apparatus 1000 is, for example, an electronic apparatussuch as an imaging apparatus such as a digital still camera and a videocamera, and a portable terminal apparatus such as a smartphone and atablet terminal.

The electronic apparatus 1000 includes a solid-state imaging device1001, a DSP circuit 1002, a frame memory 1003, a display unit 1004, arecording unit 1005, an operation unit 1006, and a power source unit1007. Further, in the electronic apparatus 1000, the DSP circuit 1002,the frame memory 1003, the display unit 1004, the recording unit 1005,the operation unit 1006, and the power source unit 1007 are connected toeach other via a bus line 1008.

The solid-state imaging device 1001 corresponds to the above-mentionedCMOS image sensor 10 (FIG. 1 ), and the pixels 100 shown in theabove-mentioned first to ninth embodiments can be employed as the pixels100 two-dimensionally arranged in the pixel array unit 11 (FIG. 1 ).Accordingly, in the electronic apparatus 1000, it is possible to detectphase difference on the basis of the signal for phase differencedetection acquired from the pixels 100 (image surface phase differencepixels) shown in the above-mentioned first to ninth embodiments, andperform control of focusing on an in-focus object.

Further, as the pixels to be two-dimensionally arranged in the pixelarray unit 11 (FIG. 1 ), the pixels 200, the pixels 300, the pixels 400,or the pixels 500 shown in the above-mentioned tenth to thirteenthembodiments may be arranged. Also in this case, in the electronicapparatus 1000, it is possible to detect phase difference on the basisof the signal for phase difference detection acquired from the pixels200, the pixels 300, the pixels 400, or the pixels 500, and performcontrol of focusing on an in-focus object.

Note that since the pixel 100 has a structure (2PD structure) in whichthe two photoelectric conversion devices 113A and 113B are provided forone on-chip lens 111, the pixel signal (A+B signal) generated by addingup the charges accumulated in the photoelectric conversion devices 113Aand 113B is used as a signal for acquiring an image, and the pixelsignal (A signal) obtained from the charges accumulated in thephotoelectric conversion device 113A and the pixel signal (B signal)obtained from the charges accumulated in the photoelectric conversiondevice 113B can be independently read and used as a signal for detectinga phase difference.

As described above, the pixel 100 has a 2PD structure, and can be usedas both a pixel for acquiring an image and a pixel for detecting a phasedifference (image plane phase difference detection pixel). Further,although detailed description is omitted, similarly, also the pixel 200,the pixel 300, the pixel 400, and the pixel 500 can be used as both apixel for acquiring an image and a pixel for detecting a phasedifference because they have a 2PD structure.

The DSP circuit 1002 is a camera signal processing circuit thatprocesses a signal supplied from the solid-state imaging device 1001.The DSP circuit 1002 outputs image data acquired by processing thesignal from the solid-state imaging device 1001. The frame memory 1003temporarily stores, in units of frames, the image data processed by theDSP circuit 1002.

The display unit 1004 includes, for example, a panel display apparatussuch as a liquid crystal panel and an organic EL (Electro Luminescence)panel, and displays a moving image or a still image imaged by thesolid-state imaging device 1001. The recording unit 1005 stores theimage data of the moving image or still image imaged by the solid-stateimaging device 1001 in a recording medium such as a semiconductor memoryand a hard disk.

The operation unit 1006 outputs operation commands for various functionsof the electronic apparatus 1000 in accordance with a user operation.The power source unit 1007 appropriately supplies various kinds of powersources as operation power sources for the DSP circuit 1002, the framememory 1003, the display unit 1004, the recording unit 1005, and theoperation unit 1006 to these supply targets.

The electronic apparatus 1000 is configured as described above. Anembodiment of the present technology is applied to the solid-stateimaging device 1001, as described above. Specifically, the CMOS imagesensor 10 (FIG. 1 ) can be applied to the solid-state imaging device1001. By applying an embodiment of the present technology to thesolid-state imaging device 1001 and forming a projection portion by theinter-pixel light blocking unit 114 or the inter-pixel separation unit115 in an area in which the contribution of isolation is low in thepixel 100, it is possible to improve the accuracy of phase differencedetection while suppressing degradation of a picked-up image.

7. Usage Examples of Solid-State Imaging Device

FIG. 64 is a diagram showing usage examples of a solid-state imagingdevice to which an embodiment of the present technology is applied.

The CMOS image sensor 10 (FIG. 1 ) can be used in various cases ofsensing light such as visible light, infrared light, ultraviolet light,and X-rays as follows, for example. That is, as shown in FIG. 64 , theCMOS image sensor 10 can be used for not only an apparatus used in theappreciation field for photographing images to be viewed but alsoapparatuses used in the traffic field, the home electronics field, themedical and healthcare field, the security field, the beauty care field,the sports field, and the agriculture field, for example.

Specifically, in the appreciation field, the CMOS image sensor 10 can beused for an apparatus for photographing images to be viewed (e.g., theelectronic apparatus 1000 shown in FIG. 63 ), such as a digital camera,a smartphone, and a camera-equipped mobile phone.

In the traffic field, the CMOS image sensor 10 can be used for anapparatus used for traffic purposes, such as a car-mounted sensor thatphotographs front/rear/periphery/inside of an automobile, a surveillancecamera that monitors running vehicles and roads, and a distancemeasurement sensor that measures distances among vehicles, for safedriving including automatic stop, recognition of a driver condition, andthe like.

In the home electronics field, the CMOS image sensor 10 can be used foran apparatus used in home electronics such as a television receiver, arefrigerator, and an air conditioner, for photographing gestures ofusers and executing apparatus operations according to the gestures.Further, in the medical and healthcare field, the CMOS image sensor 10can be used for an apparatus used for medical and healthcare purposes,such as an endoscope and an apparatus that performs blood vesselphotographing by receiving infrared light.

In the security field, the CMOS image sensor 10 can be used for anapparatus used for security purposes, such as a surveillance camera forcrime-prevention purposes and a camera for person authenticationpurposes. Further, in the beauty care field, the CMOS image sensor 10can be used for an apparatus used for beauty care purposes, such as askin measurement apparatus that photographs skins and a microscope thatphotographs scalps.

In the sports field, the CMOS image sensor 10 can be used for anapparatus used for sports purposes, such as an action camera and awearable camera for sports purposes. Further, in the agriculture field,the CMOS image sensor 10 can be used for an apparatus for agriculturepurposes, such as a camera for monitoring states of fields and crops.

8. Configuration Example of Stacked-Type Solid-State Imaging Device towhich Technology According to Present Disclosure can be Applied

FIG. 65 is a diagram showing the outline of a configuration example ofthe stacked-type solid-state imaging device to which the technologyaccording to the present disclosure can be applied.

A of FIG. 65 shows a schematic configuration example of anon-stacked-type solid-state imaging device. As shown in A of FIG. 65 ,a solid-state imaging device 23010 includes a single die (semiconductorsubstrate) 23011. This die 23011 installs a pixel region 23012 in whichpixels are arranged in an array, a control circuit 23013 that controlsdriving of the pixels and performs other various controls, and a logiccircuit 23014 for signal processing.

B and C of FIG. 65 show a schematic configuration example of thestacked-type solid-state imaging device. As shown in B and C of FIG. 65, two dies of a sensor die 23021 and a logic die 23024 are stacked andelectrically connected to each other. In this manner, the solid-stateimaging device 23020 is configured as a single semiconductor chip.

In B of FIG. 65 , the sensor die 23021 installs the pixel region 23012and the control circuit 23013. The logic die 23024 installs the logiccircuit 23014 including a signal processing circuit that performs signalprocessing.

In C of FIG. 65 , the sensor die 23021 installs the pixel region 23012.The logic die 23024 installs the control circuit 23013 and the logiccircuit 23014.

FIG. 66 is a cross-sectional view showing a first configuration exampleof the stacked-type solid-state imaging device 23020.

In the sensor die 23021, a photodiode (PD), a floating diffusion (FD),and transistors (Tr) (MOS FET), which constitute a pixel that becomesthe pixel region 23012, and Tr and the like, which become the controlcircuit 23013, are formed. In addition, a wiring layer 23101 is formedin the sensor die 23021. The wiring layer 23101 includes a plurality oflayers, in this example, three-layer wires 23110. Note that (Tr thatbecomes) the control circuit 23013 can be formed in not the sensor die23021 but the logic die 23024.

Tr constituting the logic circuit 23014 is formed in the logic die23024. In addition, a wiring layer 23161 is formed in the logic die23024. The wiring layer 23161 includes a plurality of layers, in thisexample, three-layer wires 23170. Further, a connection hole 23171 isformed in the logic die 23024. The connection hole 23171 has aninsulation film 23172 formed on an inner wall surface thereof. Aconnection conductor 23173 to be connected to the wire 23170 and thelike is embedded in the connection hole 23171.

The sensor die 23021 and the logic die 23024 are bonded to each othersuch that the wiring layers 23101 and 23161 thereof face each other.With this, the stacked-type solid-state imaging device 23020 in whichthe sensor die 23021 and the logic die 23024 are stacked is formed. Afilm 23191 such as a protection film is formed in a face on which thesensor die 23021 and the logic die 23024 are bonded to each other.

A connection hole 23111 is formed in the sensor die 23021. Theconnection hole 23111 penetrates the sensor die 23021 from the backside(side on which light enters the PD) (upper side) of the sensor die 23021and reaches an uppermost layer wire 23170 of the logic die 23024. Inaddition, a connection hole 23121 is formed in the sensor die 23021. Theconnection hole 23121 is located in proximity of the connection hole23111 and reaches a first-layer wire 23110 from the backside of thesensor die 23021. An insulation film 23112 is formed on an inner wallsurface of the connection hole 23111. An insulation film 23122 is formedon an inner wall surface of the connection hole 23121. Then, connectionconductors 23113 and 23123 are embedded in the connection holes 23111and 23121, respectively. The connection conductor 23113 and theconnection conductor 23123 electrically connected to each other on theback side of the sensor die 23021. With this, the sensor die 23021 andthe logic die 23024 are electrically connected to each other via thewiring layer 23101, the connection hole 23121, the connection hole23111, and the wiring layer 23161.

FIG. 67 is a cross-sectional view showing a second configuration exampleof the stacked-type solid-state imaging device 23020.

In a second configuration example of the solid-state imaging device23020, ((the wire 23110 of) the wiring layer 23101 of) the sensor die23021 and ((the wire 23170 of) the wiring layer 23161 of) the logic die23024 are electrically connected to each other through a singleconnection hole 23211 formed in the sensor die 23021.

That is, in FIG. 67 , the connection hole 23211 is formed penetratingthe sensor die 23021 from the back side of the sensor die 23021 andreaching an uppermost layer wire 23170 of the logic die 23024 and anuppermost layer wire 23110 of the sensor die 23021. An insulation film23212 is formed on the inner wall surface of the connection hole 23211.A connection conductor 23213 is embedded in the connection hole 23211.In FIG. 66 described above, the sensor die 23021 and the logic die 23024are electrically connected to each other through the two connectionholes 23111 and 23121. On the other hand, in FIG. 67 , the sensor die23021 and the logic die 23024 are electrically connected to each otherthrough the single connection hole 23211.

FIG. 68 is a cross-sectional view showing a third configuration exampleof the stacked-type solid-state imaging device 23020.

In the solid-state imaging device 23020 of FIG. 68 , the film 23191 suchas the protection film is not formed in a face on which the sensor die23021 and the logic die 23024 are bonded to each other. In the case ofFIG. 66 , the film 23191 such as the protection film is formed in theface on which the sensor die 23021 and the logic die 23024 are bonded toeach other. In this point, the solid-state imaging device 23020 of FIG.68 is different from the case of FIG. 66 .

The sensor die 23021 and the logic die 23024 are superimposed on eachother such that the wires 23110 and 23170 are held in direct contact.Then, the wires 23110 and 23170 are directly joined with each other byheating the wires 23110 and 23170 while adding necessary weight on thewires 23110 and 23170. In this manner, the solid-state imaging device23020 of FIG. 68 is formed.

FIG. 69 is a cross-sectional view showing another configuration exampleof the stacked-type solid-state imaging device to which the technologyaccording to the present disclosure can be applied.

In FIG. 69 , a solid-state imaging device 23401 has a three-layerlaminate structure. In this three-layer laminate structure, three diesof a sensor die 23411, a logic die 23412, and a memory die 23413 arestacked.

The memory die 23413 includes a memory circuit. The memory circuitstores data temporarily necessary in signal processing performed in thelogic die 23412, for example.

In FIG. 69 , the logic die 23412 and the memory die 23413 are stackedbelow the sensor die 23411 in the stated order. However, the logic die23412 and the memory die 23413 may be stacked below the sensor die 23411in inverse order, i.e., in the order of the memory die 23413 and thelogic die 23412.

Note that, in FIG. 69 , a PD that becomes a photoelectric conversionportion of the pixel and source/drain regions of a pixel Tr are formedin the sensor die 23411.

A gate electrode is formed via a gate insulation film around the PD. Apixel Tr 23421 and a pixel Tr 23422 are formed by the gate electrode andthe paired source/drain regions.

The pixel Tr 23421 adjacent to the PD is a transfer Tr. One of thepaired source/drain regions that constitute the pixel Tr 23421 is an FD.

Further, an inter-layer insulation film is formed in the sensor die23411. A connection hole is formed in the inter-layer insulation film.The pixel Tr 23421 and connection conductors 23431 that connects to thepixel Tr 23422 are formed in the connection hole.

In addition, a wiring layer 23433 having a plurality of layers withlayer wires 23432 which connect to each of the connection conductors23431 is formed in the sensor die 23411.

Further, an aluminum pad 23434 that becomes an electrode for externalconnection is formed in a lowermost layer of the wiring layer 23433 ofthe sensor die 23411. That is, in the sensor die 23411, the aluminum pad23434 is formed at a position closer to a surface 23440 bonding with thelogic die 23412 than the wires 23432. The aluminum pad 23434 is used asone end of a wire associated with input/output of signals into/from theoutside.

In addition, a contact 23441 used for electric connection with the logicdie 23412 is formed in the sensor die 23411. The contact 23441 isconnected to a contact 23451 of the logic die 23412 and also connectedto an aluminum pad 23442 of the sensor die 23411.

Then, a pad hole 23443 is formed in the sensor die 23411, reaching thealuminum pad 23442 from a backside (upper side) of the sensor die 23411.

The technology according to the present disclosure can also be appliedto the solid-state imaging device as described above.

9. Example of Application to Movable Object

The technology according to the present disclosure (the presenttechnology) is applicable to various products. For example, thetechnology according to the present disclosure may be, for example,realized as a device mounted on any kind of movable objects such as acar, an electric car, a hybrid electric car, a motorcycle, a bicycle, apersonal mobility, an aircraft, a drone, a ship, and a robot.

FIG. 70 is a block diagram showing an example of a schematicconfiguration of a vehicle control system, which is an example of amovable object control system to which the technology according to thepresent disclosure is applied.

A vehicle control system 12000 includes a plurality of electroniccontrol units connected to each other via a communication network 12001.In the example of FIG. 70 , the vehicle control system 12000 includes adrive-system control unit 12010, a body-system control unit 12020, avehicle exterior information detection unit 12030, a vehicle interiorinformation detection unit 12040, and an integrated-control unit 12050.Further, as the functional configuration of the integrated-control unit12050, a microcomputer 12051, a sound/image output unit 12052, and anin-vehicle network interface (I/F) 12053 are shown.

The drive-system control unit 12010 executes various kinds of programs,to thereby control the operations of the devices related to the drivesystem of the vehicle. For example, the drive-system control unit 12010functions as a control device that controls driving force generationdevices such as an internal-combustion engine and a driving motor forgenerating a driving force of the vehicle, a driving force transmissionmechanism for transmitting the driving force to wheels, a steeringmechanism that adjusts the steering angle of the vehicle, a brake devicethat generates a braking force of the vehicle, and the like.

The body-system control unit 12020 executes various kinds of programs,to thereby control the operations of the various kinds devices equippedin a vehicle body. For example, the body-system control unit 12020functions as a control device that controls a keyless entry system, asmart key system, a power window device, or various lamps such as headlamps, back lamps, brake lamps, side-turn lamps, and fog lamps. In thiscase, an electric wave transmitted from a mobile device in place of akey or signals from various switches may be input in the body-systemcontrol unit 12020. The body-system control unit 12020 receives theinput electric wave or signal, and controls a door lock device, thepower window device, the lamps, and the like of the vehicle.

The vehicle exterior information detection unit 12030 detectsinformation outside the vehicle including the vehicle control system12000. For example, an image capture unit 12031 is connected to thevehicle exterior information detection unit 12030. The vehicle exteriorinformation detection unit 12030 causes the image capture unit 12031 tocapture an environment image and receives the captured image. Thevehicle exterior information detection unit 12030 may perform an objectdetection process of detecting a man, a vehicle, an obstacle, a sign, asignage on a road, or the like on the basis of the received image, ormay perform a distance detection process on the basis of the receivedimage.

The image capture unit 12031 is an optical sensor that receives lightand outputs an electric signal corresponding to the amount of lightreceived. The image capture unit 12031 may output the electric signal asan image or may output as distance measurement information. Further, thelight that the image capture unit 12031 receives may be visible light orinvisible light such as infrared light.

The vehicle interior information detection unit 12040 detects vehicleinterior information. For example, a driver condition detector 12041that detects the condition of a driver is connected to the vehicleinterior information detection unit 12040. For example, the drivercondition detector 12041 may include a camera that captures an image ofa driver. The vehicle interior information detection unit 12040 maycalculate the fatigue level or the concentration level of the driver onthe basis of the detected information input from the driver conditiondetector 12041, and may determine whether the driver is sleeping.

The microcomputer 12051 may calculate the control target value of thedriving force generation device, the steering mechanism, or the brakedevice on the basis of the vehicle interior/vehicle exterior informationobtained by the vehicle exterior information detection unit 12030 or thevehicle interior information detection unit 12040, and may output acontrol command to the drive-system control unit 12010. For example, themicrocomputer 12051 may perform coordinated control for the purpose ofrealizing the advanced driver assistance system (ADAS) functionincluding avoiding a vehicle collision, lowering impacts of a vehiclecollision, follow-up driving based on a distance between vehicles,constant speed driving, vehicle collision warning, a vehicle's lanedeparture warning, or the like.

Further, by controlling the driving force generation device, thesteering mechanism, the brake device, or the like on the basis ofinformation about the environment around the vehicle obtained by thevehicle exterior information detection unit 12030 or the vehicleinterior information detection unit 12040, the microcomputer 12051 mayperform coordinated control for the purpose of realizing self-driving,i.e., autonomous driving without the need of drivers' operations, andthe like.

Further, the microcomputer 12051 may output a control command to thebody-system control unit 12020 on the basis of vehicle exteriorinformation obtained by the vehicle exterior information detection unit12030. For example, the microcomputer 12051 may perform coordinatedcontrol including controlling the head lamps on the basis of thelocation of a leading vehicle or an oncoming vehicle detected by thevehicle exterior information detection unit 12030 and changing highbeams to low beams, for example, for the purpose of anti-glare.

The sound/image output unit 12052 transmits at least one of a soundoutput signal and an image output signal to an output device, which iscapable of notifying a passenger of the vehicle or a person outside thevehicle of information visually or auditorily. In the example of FIG. 70, an audio speaker 12061, a display unit 12062, and an instrument panel12063 are shown as examples of the output devices. For example, thedisplay unit 12062 may include at least one of an on-board display and ahead-up display.

FIG. 71 is a diagram showing examples of mounting positions of the imagecapture units 12031.

In FIG. 71 , a vehicle 12100 includes, as the image capture units 12031,image capture units 12101, 12102, 12103, 12104, and 12105.

For example, the image capture units 12101, 12102, 12103, 12104, and12105 are provided at positions such as the front nose, the side-viewmirrors, the rear bumper or the rear door, and an upper part of thewindshield in the cabin of the vehicle 12100. Each of the image captureunit 12101 on the front nose and the image capture unit 12105 on theupper part of the windshield in the cabin mainly obtains an image of thefront of the vehicle 12100. Each of the image capture units 12102 and12103 on the side-view mirrors mainly obtains an image of a side of thevehicle 12100. The image capture unit 12104 on the rear bumper or therear door mainly obtains an image of the rear of the vehicle 12100. Theimage capture unit 12105 provided on the upper part of the windshield inthe cabin is mainly used for detecting a leading vehicle or detecting apedestrian, an obstacle, a traffic light, a traffic sign, a lane, or thelike.

Note that FIG. 71 shows examples of image capture ranges of the imagecapture units 12101 to 12104. The image capture range 12111 indicatesthe image capture range of the image capture unit 12101 on the frontnose, the image capture ranges 12112 and 12113 indicate the imagecapture ranges of the image capture units 12102 and 12103 on theside-view mirrors, respectively, and the image capture range 12114indicates the image capture range of the image capture unit 12104 on therear bumper or the rear door. For example, by overlaying the image datacaptured by the image capture units 12101 to 12104 each other, a planeimage of the vehicle 12100 as viewed from above is obtained.

At least one of the image capture units 12101 to 12104 may have afunction of obtaining distance information. For example, at least one ofthe image capture units 12101 to 12104 may be a stereo camera includinga plurality of image sensors or an image sensor including pixels forphase difference detection.

For example, by obtaining the distance between the vehicle 12100 andeach three-dimensional (3D) object in the image capture ranges 12111 to12114 and the temporal change (relative speed to the vehicle 12100) ofthe distance on the basis of the distance information obtained from theimage capture units 12101 to 12104, the microcomputer 12051 may extract,as a leading vehicle, a 3D object which is especially the closest 3Dobject driving on the track on which the vehicle 12100 is driving at apredetermined speed (e.g., 0 km/h or more) in the directionsubstantially the same as the driving direction of the vehicle 12100.Further, by presetting a distance between the vehicle 12100 and aleading vehicle to be secured, the microcomputer 12051 may performautobrake control (including follow-up stop control), automaticacceleration control (including follow-up start-driving control), andthe like. In this way, it is possible to perform coordinated control forthe purpose of realizing self-driving, i.e., autonomous driving withoutthe need of drivers' operations, and the like.

For example, the microcomputer 12051 may sort 3D object data of 3Dobjects into motorcycles, standard-size vehicles, large-size vehicles,pedestrians, and the other 3D objects such as utility poles on the basisof the distance information obtained from the image capture units 12101to 12104, extract data, and use the data to automatically avoidobstacles. For example, the microcomputer 12051 sorts obstacles aroundthe vehicle 12100 into obstacles that a driver of the vehicle 12100 cansee and obstacles that it is difficult for the driver to see. Then, themicrocomputer 12051 determines a collision risk, which indicates ahazard level of a collision with each obstacle. When the collision riskis a preset value or more and when there is a possibility of a collisionoccurrence, the microcomputer 12051 may perform driving assistance toavoid a collision, in which the microcomputer 12051 outputs warning tothe driver via the audio speaker 12061 or the display unit 12062, ormandatorily reduces the speed or performs collision-avoidance steeringvia the drive-system control unit 12010.

At least one of the image capture units 12101 to 12104 may be aninfrared camera that detects infrared light. For example, themicrocomputer 12051 may recognize a pedestrian by determining whether ornot images captured by the image capture units 12101 to 12104 includethe pedestrian. The method of recognizing a pedestrian includes, forexample, the step of extracting characteristic points in the imagescaptured by the image capture units 12101 to 12104 being infraredcameras, and the step of performing the pattern matching process withrespect to a series of characteristic points indicating an outline of anobject, to thereby determine whether or not the object is a pedestrian.Where the microcomputer 12051 determines that the images captured by theimage capture units 12101 to 12104 include a pedestrian and recognizesthe pedestrian, the sound/image output unit 12052 controls the displayunit 12062 to display a rectangular contour superimposed on therecognized pedestrian to emphasize the pedestrian. Further, thesound/image output unit 12052 may control the display unit 12062 todisplay an icon or the like indicating a pedestrian at a desiredposition.

The above describes an example of the vehicle control system to whichthe technology according to the present disclosure may be applied. Thetechnology according to the present disclosure may be applied to theimage capture unit 12031 having the above-mentioned configuration.Specifically, the CMOS image sensor 10 shown in FIG. 1 can be applied tothe image capture unit 12031. The image capture unit 12031, to which thetechnology according to the present disclosure is applied, is effectivefor more accurately recognizing an obstacle such as a pedestrian byacquiring a picked-up image with higher quality, because it is possibleto improve the accuracy of phase difference detection while suppressingdegradation of a picked-up image.

Note that embodiments of the present technology are not limited to theabove-mentioned embodiments but various modifications can be madewithout departing from the gist of the present technology.

It should be noted that the present technology can also take thefollowing configurations.

(1)

-   -   A solid-state imaging device, including:    -   a pixel array unit, a plurality of pixels being        two-dimensionally arranged in the pixel array unit, a plurality        of photoelectric conversion devices being formed with respect to        one on-chip lens in each of the plurality of pixels, a part of        at least one of an inter-pixel separation unit formed between        the plurality of pixels and an inter-pixel light blocking unit        formed between the plurality of pixels protruding toward a        center of the corresponding pixel in a projecting shape to form        a projection portion.

(2)

-   -   The solid-state imaging device according to (1) above, in which    -   each of the plurality of pixels is a square unit pixel, and    -   the projection portion is formed toward a center of the square        unit pixel.

(3)

-   -   The solid-state imaging device according to (2) above, in which    -   the inter-pixel separation unit is formed of a material embedded        in a trench formed in a square lattice in a semiconductor layer        in which the plurality of photoelectric conversion devices are        formed, and physically separates adjacent pixels, and    -   a part of the inter-pixel separation unit protrudes toward the        center of the square unit pixel in a projecting shape to form        the projection portion.

(4)

-   -   The solid-state imaging device according to (2) above, in which    -   the inter-pixel light blocking unit is formed of a material        formed in a square lattice in an area between the on-chip lens        and a semiconductor layer in which the plurality of        photoelectric conversion devices are formed, and blocks light        between adjacent pixels, and    -   a part of the inter-pixel light blocking unit protrudes toward        the center of the square unit pixel in a projecting shape to        form the projection portion.

(5)

-   -   The solid-state imaging device according to (2) above, in which    -   the inter-pixel separation unit is formed of a material embedded        in a trench formed in a square lattice in a semiconductor layer        in which the plurality of photoelectric conversion devices are        formed, and physically separates adjacent pixels,    -   the inter-pixel light blocking unit is formed of a material        formed in a square lattice in an area between the on-chip lens        and a semiconductor layer in which the plurality of        photoelectric conversion devices are formed, and blocks light        between adjacent pixels, and    -   a part of the inter-pixel separation unit and a part of the        inter-pixel light blocking unit protrude toward the center of        the square unit pixel in a projecting shape to form the        projection portion.

(6)

-   -   The solid-state imaging device according to any one of (1)        to (5) above, in which    -   the square unit pixel forms an R pixel, a G pixel, or a B pixel        corresponding to a red (R), green (G), or blue (B) color filter        located immediately below the on-chip lens, respectively, and    -   the projection portion is formed with respect to at least one of        the R pixel, the G pixel, and the B pixel among the plurality of        pixels arranged in the pixel array unit.

(7)

-   -   The solid-state imaging device according to (6) above, in which    -   the projection portion is formed with respect to only the R        pixel, the G pixel, or the B pixel.

(8)

-   -   The solid-state imaging device according to (6) above, in which    -   the projection portion is formed with respect to all of the R        pixel, the G pixel, and the B pixel.

(9)

-   -   The solid-state imaging device according to (6) above, in which    -   the projection portion is formed with respect to a combination        of two pixels out of the R pixel, the G pixel, and the B pixel.

(10)

-   -   The solid-state imaging device according to any one of (6)        to (9) above, in which    -   a projecting length of the projection portion differs for each        of the R pixel, the G pixel, and the B pixel.

(11)

-   -   The solid-state imaging device according to any one of (2)        to (10) above, in which    -   a protruding length of the projection portion is determined        depending on a focused spot diameter of the on-chip lens.

(12)

-   -   The solid-state imaging device according to (11) above, in which    -   the protruding length of the projection portion corresponds to        one seventh to one fourth a length of a side of a pitch of the        on-chip lens.

(13)

-   -   The solid-state imaging device according to any one of (2)        to (12) above, in which    -   a depth of a cross section of the projection portion with        respect to a surface on a light incident side differs for each        projecting part having a projecting shape.

(14)

-   -   The solid-state imaging device according to any one of (3)        to (5) above, in which    -   the trench is formed from a first surface that is a surface on a        light incident side or a second surface that is a surface        opposite to the light incident side.

(15)

-   -   The solid-state imaging device according to any one of (2)        to (14) above, in which    -   in the square unit pixel, the plurality of photoelectric        conversion devices formed in a semiconductor layer are separated        by an impurity.

(16)

-   -   The solid-state imaging device according to any one of (2)        to (15) above, in which    -   an output of each of the plurality of photoelectric conversion        devices is used for phase difference detection.

(17)

-   -   A solid-state imaging device, including:    -   a pixel array unit, a plurality of pixels being        two-dimensionally arranged in the pixel array unit, one        photoelectric conversion device being formed in each of the        plurality of pixels, the pixel array unit including pixels        arranged with respect to one on-chip lens, a part of at least        one of an inter-pixel separation unit formed between pixels        constituting the pixels arranged with respect to the one on-chip        lens and an inter-pixel light blocking unit formed between the        pixels constituting the pixels arranged with respect to the one        on-chip lens protruding toward a center of the pixels arranged        with respect to the one on-chip lens in a projecting shape to        form a projection portion.

(18)

-   -   The solid-state imaging device according to (17) above, in which    -   the on-chip lens has an elliptical shape covering two        consecutive pixels in a row direction or a column direction, and    -   a part of at least one of the inter-pixel separation unit and        the inter-pixel light blocking unit protrudes between the two        consecutive pixels to form the projection portion.

(19)

-   -   The solid-state imaging device according to (17) above, in which    -   the on-chip lens has a circular shape covering four pixels in        two rows and two columns, and    -   a part of at least one of the inter-pixel separation unit and        the inter-pixel light blocking unit protrudes toward a center of        the four pixels to form the projection portion.

(20)

-   -   An electronic apparatus, including:    -   a solid-state imaging device including        -   a pixel array unit, a plurality of pixels being            two-dimensionally arranged in the pixel array unit, a            plurality of photoelectric conversion devices being formed            with respect to one on-chip lens in each of the plurality of            pixels, a part of at least one of an inter-pixel separation            unit formed between the plurality of pixels and an            inter-pixel light blocking unit formed between the plurality            of pixels protruding toward a center of the corresponding            pixel in a projecting shape to form a projection portion.

(21)

-   -   A solid-state imaging device, comprising:    -   a pixel array unit, a plurality of pixels being        two-dimensionally arranged in the pixel array unit, the        plurality of pixels including a pixel in which a plurality of        photoelectric conversion devices is formed with respect to one        on-chip lens, in which    -   a fixed charge amount differs between a first area between the        plurality of photoelectric conversion devices and a second area        excluding the first area on an interface on a side of a light        incident surface in a semiconductor layer in which the plurality        of photoelectric conversion devices is formed or in a vicinity        thereof.

(22)

-   -   The solid-state imaging device according to (21) above, in which    -   the fixed charge amount in the first area is larger than the        fixed charge amount in the second area.

(23)

-   -   The solid-state imaging device according to (21) or (22) above,        in which    -   an insulation layer formed on the semiconductor layer includes        an oxide film, a first film of a part corresponding to the first        area, and a second film of a part corresponding to the second        area, and    -   the first film and the second film include different high        dielectric constant films.

(24)

-   -   The solid-state imaging device according to (23) above, in which    -   two or more different high dielectric constant films are stacked        in at least one of the first film or the second film.

(25)

-   -   The solid-state imaging device according to (24) above, in which    -   the number of stacked layers in the first film is larger than        that in the second film.

(26)

-   -   The solid-state imaging device according to (21) or (22) above,        in which    -   an insulation layer formed on the semiconductor layer includes        an oxide film and a high dielectric constant film, and    -   a part corresponding to the first area and a part corresponding        to the second area in the insulation layer have different        thicknesses of the oxide film.

(27)

-   -   The solid-state imaging device according to any one of (21)        to (26) above, in which    -   the pixel is configured as a pixel of a color corresponding to a        color filter disposed immediately below the on-chip lens.

(28)

-   -   The solid-state imaging device according to (27) above, in which    -   a first photoelectric conversion device formed in a pixel        corresponding to a first color and a photoelectric conversion        device formed in a pixel corresponding to a second color        different from the first color are separated from each other by        impurities.

(29)

-   -   The solid-state imaging device according to (27) above, in which    -   a first photoelectric conversion device formed in a pixel        corresponding to a first color and a photoelectric conversion        device formed in a pixel corresponding to a second color        different from the first color are separated from each other by        an inter-pixel separation unit containing an oxide film or        metal.

(30)

-   -   The solid-state imaging device according to (27) above, in which    -   a transparent electrode is formed between the plurality of        photoelectric conversion devices formed in a pixel corresponding        to a specific color.

(31)

-   -   The solid-state imaging device according to any one of (27)        to (30) above, in which    -   the pixel includes an R pixel, a G pixel, and a B pixel.

(32)

-   -   An electronic apparatus, comprising:    -   a solid-state imaging device that includes a pixel array unit, a        plurality of pixels being two-dimensionally arranged in the        pixel array unit, the plurality of pixels including a pixel in        which a plurality of photoelectric conversion devices is formed        with respect to one on-chip lens, in which    -   a fixed charge amount differs between a first area between the        plurality of photoelectric conversion devices and a second area        excluding the first area on an interface on a side of a light        incident surface in a semiconductor layer in which the plurality        of photoelectric conversion devices is formed or in a vicinity        thereof.

(33)

-   -   A solid-state imaging device, comprising:    -   a pixel array unit, a plurality of pixels being        two-dimensionally arranged in the pixel array unit, the        plurality of pixels including a pixel in which a plurality of        photoelectric conversion devices is formed with respect to one        on-chip lens, in which    -   a first separation area is formed between the plurality of        photoelectric conversion devices formed in a pixel corresponding        to a specific color, a first embedding device containing a        low-refractive material being embedded in the first separation        area, and    -   a second separation area is formed between a first photoelectric        conversion device formed in a pixel corresponding to a first        color and a second photoelectric conversion device formed in a        pixel corresponding to a second color different from the first        color, a second embedding device containing metal being embedded        in the second separation area.

(34)

-   -   The solid-state imaging device according to (33) above, in which    -   a cross section of the first separation area has a tapered shape        in which a width increases as approaching a surface on a light        incident side.

(35)

-   -   The solid-state imaging device according to (34) above, in which    -   the cross section of the first separation area has a triangular        shape.

(36)

-   -   The solid-state imaging device according to (35) above, in which    -   the first embedding device disappears at a predetermined depth        from the surface on the light incident side in the cross section        of the first separation area, and    -   an area below the first separation area is separated by        impurities.

(37)

-   -   The solid-state imaging device according to (34) above, in which    -   the cross section of the first separation area has a triangular        shape from the surface on the light incident side to a        predetermined depth and a rectangular shape below the        predetermined depth.

(38)

-   -   The solid-state imaging device according to (34) above, in which    -   the cross section of the first separation area has a trapezoidal        shape tapered from the surface on the light incident side to a        surface on a side opposite to the light incident side.

(39)

-   -   The solid-state imaging device according to any one of (33)        to (38) above, in which    -   a plane of the first separation area has a rectangular shape        when viewed from the surface on the light incident side.

(40)

-   -   The solid-state imaging device according to any one of (33)        to (38) above, in which    -   a plane of the first separation area has a rhombus shape when        viewed from the surface on the light incident side.

(41)

-   -   The solid-state imaging device according to any one of (33)        to (40) above, in which    -   the second embedding device further contains a low-refractive        material, and    -   the metal is embedded from the surface on the light incident        side to a predetermine depth and the low-refractive material is        embedded from a surface on a side opposite to the light incident        side to a predetermined depth in a cross section of the second        separation area.

(42)

-   -   The solid-state imaging device according to any one of (33)        to (41) above, in which    -   a fixed charge film is formed on a side wall of the second        separation area.

(43)

-   -   The solid-state imaging device according to any one of (33)        to (42) above, in which    -   the pixel is configured as a pixel of a color corresponding to a        color filter disposed immediately below the on-chip lens.

(44)

-   -   The solid-state imaging device according to (43) above, in which    -   the pixel includes an R pixel, a G pixel, and a B pixel.

(45)

-   -   An electronic apparatus, comprising:    -   a solid-state imaging device that includes a pixel array unit, a        plurality of pixels being two-dimensionally arranged in the        pixel array unit, the plurality of pixels including a pixel in        which a plurality of photoelectric conversion devices is formed        with respect to one on-chip lens, in which    -   a first separation area is formed between the plurality of        photoelectric conversion devices formed in a pixel corresponding        to a specific color, a first embedding device containing a        low-refractive material being embedded in the first separation        area, and    -   a second separation area is formed between a first photoelectric        conversion device formed in a pixel corresponding to a first        color and a second photoelectric conversion device formed in a        pixel corresponding to a second color different from the first        color, a second embedding device containing metal being embedded        in the second separation area.

(46)

-   -   A solid-state imaging device, comprising:    -   a pixel array unit, a plurality of pixels being        two-dimensionally arranged in the pixel array unit, the        plurality of pixels including a pixel in which a plurality of        photoelectric conversion devices is formed with respect to one        on-chip lens, in which    -   the on-chip lens is formed of a plurality of types of        substances.

(47)

-   -   The solid-state imaging device according to (46) above, in which    -   the on-chip lens is formed of two types of substances having        different refractive indexes.

(48)

-   -   The solid-state imaging device according to (47) above, in which    -   the on-chip lens is formed a first member having a first        refractive index and a second member having a second refractive        index lower than the first refractive index,    -   the first member includes a curved surface on which light is        incident, and a part corresponding to a part having a V shape of        the second member, and    -   the second member includes a surface on a side opposite to the        curved surface on which light is incident and the part having a        V shape.

(49)

-   -   The solid-state imaging device according to (46) above, in which    -   the on-chip lens is formed of three types of substances having        different refractive indexes.

(50)

-   -   The solid-state imaging device according to (49) above, in which    -   the on-chip lens is formed of a first member having a first        refractive index, a second member having a second refractive        index, and a third member having a third refractive index,    -   the plurality of photoelectric conversion device formed in the        pixel is physically separated by an inter-device separation        unit,    -   the first member includes a curved surface on which light is        incident, and a part corresponding to a part having a V shape of        the second member,    -   the second member includes a surface on a side opposite to the        curved surface on which light is incident and the part having a        V shape, and    -   the third member is formed in an area corresponding to the        inter-device separation unit.

(51)

-   -   The solid-state imaging device according to (49) above, in which    -   the pixel is configured as a pixel corresponding to a specific        color, and    -   a height of the on-chip lens in the pixel differs for each        specific color.

(52)

-   -   The solid-state imaging device according to (51) above, in which    -   the pixel includes an R pixel, a G pixel, and a B pixel, and    -   the height of the on-chip lens decreases in an order of the R        pixel, the G pixel, and the B pixel.

(53)

-   -   The solid-state imaging device according to (49) above, in which    -   the pixel is configured as a pixel corresponding to a specific        color, and    -   a curvature radius of the on-chip lens in the pixel differs for        each specific color.

(54)

-   -   The solid-state imaging device according to (53) above, in which    -   the pixel includes an R pixel, a G pixel, and a B pixel, and    -   the curvature radius of the on-chip lens decreases in an order        of the R pixel, the G pixel, and the B pixel.

(55)

-   -   The solid-state imaging device according to any one of (46)        to (54) above, in which    -   the pixel is configured as a pixel of a color corresponding to a        color filter disposed immediately below the on-chip lens.

(56)

-   -   The solid-state imaging device according to (46) above, in which    -   a control member that controls a dependency on an incident angle        of light is formed for a member forming the on-chip lens.

(57)

-   -   The solid-state imaging device according to (56) above, in which    -   the on-chip lens is formed of a first member having a first        refractive index and a second member having a second refractive        index lower than the first refractive index,    -   the first member includes a curved surface on which light is        incident, and a part corresponding to a part having a V shape of        the second member,    -   the second member includes a surface on a side opposite to the        curved surface on which light is incident and the part having a        V shape, and    -   the control member is formed between the first member and the        second member.

(58)

-   -   The solid-state imaging device according to (56) or (57) above,        in which    -   the control member is a photonic crystal.

(59)

-   -   The solid-state imaging device according to any one of (56)        to (58) above, in which    -   the pixel is configured as a pixel of a color corresponding to        spectroscopy by the control member.

(60)

-   -   The solid-state imaging device according to (59) above, in which    -   the pixel includes an R pixel, a G pixel, and a B pixel.

(61)

-   -   An electronic apparatus, comprising:    -   a solid-state imaging device that includes a pixel array unit, a        plurality of pixels being two-dimensionally arranged in the        pixel array unit, the plurality of pixels including a pixel in        which a plurality of photoelectric conversion devices is formed        with respect to one on-chip lens, in which    -   the on-chip lens is formed of a plurality of types of        substances.

(62)

-   -   A solid-state imaging device, comprising:    -   a pixel array unit, a plurality of pixels being        two-dimensionally arranged in the pixel array unit, the        plurality of pixels including a pixel in which a plurality of        photoelectric conversion devices is formed with respect to one        on-chip lens, in which    -   a first vertical transistor is formed, from a surface on a side        opposite to a light incident side, between the plurality of        photoelectric conversion devices formed in a pixel corresponding        to a specific color.

(63)

-   -   The solid-state imaging device according to (62) above, in which    -   a blooming path is formed between the plurality of photoelectric        conversion devices by applying a voltage to the first vertical        transistor.

(64)

-   -   The solid-state imaging device according to (62) or (63) above,        in which    -   a second vertical transistor is formed, from the surface on the        side opposite to the light incident side, between a first        photoelectric conversion device formed in a pixel corresponding        to a first color and a second photoelectric conversion device        formed in a pixel corresponding to a second color different from        the first color.

(65)

-   -   The solid-state imaging device according to (64) above, in which    -   charges are generated by applying a voltage to the second        vertical transistor.

(66)

-   -   The solid-state imaging device according to (64) or (65) above,        in which    -   an inter-pixel separation unit is formed, from a surface on the        light incident side, between the first photoelectric conversion        device and the second photoelectric conversion device.

(67)

-   -   The solid-state imaging device according to any one of (62)        to (66) above, in which    -   the pixel is configured as a pixel of a color corresponding to a        color filter disposed immediately below the on-chip lens.

(68)

-   -   The solid-state imaging device according to (67) above, in which    -   the pixel includes an R pixel, a G pixel, and a B pixel.

(69)

-   -   An electronic apparatus, comprising:    -   a solid-state imaging device that includes a pixel array unit, a        plurality of pixels being two-dimensionally arranged in the        pixel array unit, the plurality of pixels including a pixel in        which a plurality of photoelectric conversion devices is formed        with respect to one on-chip lens, in which    -   a first vertical transistor is formed, from a surface on a side        opposite to a light incident side, between the plurality of        photoelectric conversion devices formed in a pixel corresponding        to a specific color.

REFERENCE SIGNS LIST

-   -   10 CMOS image sensor    -   11 pixel array unit    -   100, 100-ij pixel    -   111, 111E on-chip lens    -   112 color filter    -   113A, 113B photoelectric conversion device    -   114 inter-pixel light blocking unit    -   114P projection portion    -   115 inter-pixel separation unit    -   115P projection portion    -   151A, 151B transfer gate unit    -   200 pixel    -   210 silicon layer    -   211 on-chip lens    -   212 color filter    -   213A, 213B photoelectric conversion device    -   214 inter-pixel light blocking unit    -   215 inter-pixel separation unit    -   220 interface layer    -   221 central area    -   222 right-and-left area    -   230 insulation layer    -   231 oxide film    -   232A, 232B, 232C, 232D, 232E High-k film    -   233 oxide film    -   241 transparent electrode    -   300 pixel    -   310 silicon layer    -   311 on-chip lens    -   312 color filter    -   313A, 313B photoelectric conversion device    -   314 inter-pixel light blocking unit    -   315 inter-pixel separation unit    -   321 inter-same-color central portion    -   322 inter-different-color central portion    -   331 low refraction area    -   341 low refraction area    -   400 pixel    -   410 silicon layer    -   411, 411E on-chip lens    -   411A, 411B, 411C member    -   412 color filter    -   413A, 413B photoelectric conversion device    -   414 inter-pixel light blocking unit    -   415 inter-pixel separation unit    -   416 device separation unit    -   421, 421R, 421G, 421B control member    -   500 pixel    -   510 silicon layer    -   511 on-chip lens    -   512 color filter    -   513A, 513B photoelectric conversion device    -   514 inter-pixel light blocking unit    -   515 inter-pixel separation unit    -   521 inter-same-color central portion    -   522 inter-different-color central portion    -   531 vertical transistor    -   532 vertical transistor    -   1000 electronic apparatus    -   1001 solid-state imaging device    -   12031 image capture unit

What is claimed is:
 1. An imaging device, comprising: a plurality ofpixels arranged two-dimensionally in a plan view, wherein each pixel ofthe plurality of pixels includes a first photoelectric conversion regionand a second photoelectric conversion region disposed in a semiconductorsubstrate, and first material, wherein, in a cross-sectional view, thefirst material is disposed between at least a portion of the firstphotoelectric conversion region and at least a portion of the secondphotoelectric conversion region, and wherein a refractive index of thefirst material is less than a refractive index of the semiconductorsubstrate.
 2. The imaging device according to claim 1, wherein, in theplan view, the first material protrudes toward a center of acorresponding pixel.
 3. The imaging device according to claim 1,wherein, in the cross-sectional view, the first material has atriangular shape that is tapered and that decreases in width withdistance from a light incident surface of the semiconductor substrate.4. The imaging device according to claim 1, wherein the first materialis a low refractive index material.
 5. The imaging device according toclaim 1, wherein the first material is an oxide film.
 6. The imagingdevice according to claim 1, wherein the first material is glass.
 7. Theimaging device according to claim 1, wherein, in the cross-sectionalview, the first and second photoelectric conversion regions are furtherseparated by impurities in at least an area not occupied by the firstmaterial.
 8. The imaging device according to claim 7, wherein each pixelin the plurality of pixels is separated from each neighboring pixel byan inter-pixel separation unit.
 9. The imaging device according to claim8, wherein the inter-pixel separation unit is a metal.
 10. The imagingdevice according to claim 9, wherein the metal is tungsten, aluminum,silver, or rhodium.
 11. The imaging device according to claim 1, furthercomprising: a plurality of on-chip lenses, wherein each pixel in theplurality of pixels includes one on-chip lens.
 12. The imaging deviceaccording to claim 11, further comprising: a plurality of color filters,wherein each pixel in the plurality of pixels includes one color filter.13. The imaging device according to claim 12, further comprising: aninter-pixel light blocking unit that extends along boundaries of colorfilters of neighboring pixels.
 14. The imaging device according to claim1, wherein the substrate is a silicon substrate.
 15. The imaging deviceaccording to claim 11, wherein for each pixel in the plurality of pixelsa part of at least one of an inter-pixel separation unit formed betweenthe plurality of pixels and an inter-pixel light blocking unit formedbetween the plurality of pixels protrudes toward a center of acorresponding pixel in a projecting shape to form a projection portion.16. The imaging device according to claim 15, wherein, in the plan view,each pixel in the plurality of pixels is square, and wherein theprojection portion extends toward a center of the square.
 17. Theimaging device according to claim 16, wherein the inter-pixel separationunit is formed of a material embedded in a trench formed in a squarelattice in a semiconductor layer in which the photoelectric conversionregions are formed.
 18. The imaging device according to claim 15,wherein the inter-pixel separation unit is formed of a material embeddedin a trench formed in a square lattice in a semiconductor layer in whichthe photoelectric conversion regions are formed, and physicallyseparates adjacent pixels, and wherein the inter-pixel light blockingunit is formed of a material formed in a square lattice in an areabetween the on-chip lens and a semiconductor layer in which thephotoelectric conversion regions are formed and blocks light betweenadjacent pixels.
 19. The imaging device according to claim 18, wherein apart of the inter-pixel separation unit and a part of the inter-pixellight blocking unit protrude toward a center of the square unit pixel ina projecting shape to form the projection portion.
 20. The imagingdevice according to claim 19, wherein a protruding length of theprojection portion depends on a focused spot diameter of the on-chiplens.